Final Class Project by Charles Hunter

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Disclaimer and Acknowledgements This document is the result of an academic assignment for the Fall 2011 AME 30362 Design Methodology class in the Aerospace and Mechanical Engineering Department at the University of Notre Dame taught by Dr. Stephen Batill. The following page is a copy of the project assignment. The following list of students indicates their contribution to this project: • Project coordinated by Waylon Chen, Kyle Kinnary, John Moran, and Emily Reineccius. • Chapter 1 by Matthew Cirillo, Brianna Curtis, Matthew Nagy, Jeff O’Brien (Group Leader), and Hayley Reese. • Chapter 2 by Michael George, Jason Lovell, Keith Nord (Group Leader), Yichao Pan, and Mary Beth Tribble. • Chapter 3 by Kevin Eller, Eras Noel, Michael Rose, Jonathan Rosini, and Rebecca Sees (Group Leader). • Chapter 4 by Thomas Kennedy, Jennie Kim, Sean O’Connor, Joanna Whitfield (Group Leader), and Matt Wilcox. • Chapter 5 by Stephen Biddle (Group Leader), Alex Boll, Garrett Campbell, Chris Charnock, and Houston Clarke. • Chapter 6 by Kane Kimler, Kevin Klima, Matthew Lemanski, Nathan Trembley (Group Leader), and Nathaniel Walden. • Chapter 7 by Chris Borchers, John Calash, Julian Corona, Christine Dunphy, and Meg Foresman (Group Leader). • Chapter 8 by Joseph Arambula, Damon Henderson (Group Leader), Thomas McGarry, Chelsae Plageman, and Davin Sakamoto. • Chapter 9 by Ayla Bicoy, Richard Kim, Samantha Niver, Chris Payne, and Daniel Shaffer (Group Leader). • Chapter 10 by Angelo Brown, Charles Hunter, Emily Legault, Andy McCourt, and Brian Robillard (Group Leader). • Marketing presentation by Kyle Collins (Group Leader), John DeLacio, Emily Gore, Pat Hertenstein, and James Jones. • Editing, Compilation, and Graphical Design by Doug Carder, Oliver Chmell, Jason Runkle (Group Leader), Dave Simone, and Breanna Stachowski. Every effort has been made to properly cite and acknowledge all sources, but the nature of the project makes it impossible (at present) to ensure that no work has been inappropriately included or improperly cited. As such, this document should not be reprinted, sold, or otherwise distributed except in situations protected by fair use law. All opinions contained inside this document are those of the authors and do not necessarily reflect the values and beliefs of the University of Notre Dame. Examples of specific companies in the text are meant to provide benchmarks and are not meant to defame, humiliate, denounce, or injure the reputation or image of these companies. Last Edited: December 6, 2011 at 10:34am

DOCUMENT NOT INTENDED FOR PUBLIC RELEASE OR DISTRIBUTION UNIVERSITY OF NOTRE DAME DEPARTMENT OF AEROSPACE AND MECHANICAL ENGINEERING AME30362: Design Methodology, Fall 2011 Project 4 – Sustainable Design Guidelines Project Due Dates: Interim due dates to be determined as part of project Product Submission– Tues. Nov. 15, 2010 This all-class project has two goals: 1) develop a product that can assist you and other mechanical engineers in the design of sustainable products or systems, 2) work as part of a large project team to design and produce a useful product. The concepts of sustainability and sustainable design have received much attention in the recent past and all indications are their importance will only increase. This project will provide you with insights and skills to contribute to this important discussion. At the onset of this project it must be stressed that the term “sustainability” is interpreted in many different ways and it includes what can be highly emotional and complex social, economic, scientific and ethical issues. Project Description: The class will work together to design, develop and publish a document in both conventional print and webcompatible electronic formats. The project will be conducted in multiple phases and each student will contribute in various ways to the project. You will follow a process similar to a collaborative product design project. The phases will be: 1. Project formulation a. Research: Each individual will prepare a one-page project prospectus b. Organization: A group of 4 project coordinators will be selected at the beginning of the semester. They will work with the instructor, TA consultant and classmates to plan, organize, manage and evaluate this project. 2. Develop and evaluate product concepts and select a concept for implementation. 3. Implement and assess the product. Similar to many engineering projects, the deadline date and available human resources are set but the details on the required tasks and desired outcomes will evolve as the project develops. Project Requirements: Class Requirements: The class will develop a document suitable for both print and web presentation that provides useful design guidelines for mechanical engineers in the development of sustainable products and systems. The deadline for completion of the document will be Tuesday, Nov. 15, 2011. It will be submitted in both hardcopy and electronic form. A formal presentation of the final product will be conducted in class on Thursday, Dec. 8, 2011. Individual Requirements: 1. Contribute in some readily identifiable and assessable way to the project through its planning, organization, and/or implementation. 2. Prepare and submit a 1-page project prospectus (typed, 12 font) for evaluation by the project coordinators. This 1-page document (due by 11:00 a.m. Tues. Sept. 6, 2011) in .pdf format by email to batill@nd.edu) and in hardcopy submitted in class must include in a readily identifiable way: a. A list of proposed sustainability issues or topics to include in the guidelines (at least 3) b. A concept description of the form and content of the product, i.e. the design guidelines. c. A list of potential information sources for the proposed topics in sustainable design. d. A prioritized list of the top three ways in which you would like to contribute to the project. 3. Contribute as part of an assigned sub-group to develop content for the product in compliance with the guidelines provided by the project coordinators. 4. Prepare and submit a confidential peer review assessing the contributions to the project of those individuals in your sub-group. The evaluation form will be developed as part of the project.

Revised: 8/17/11

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Contents Table of Contents

List of Figures

vii

List of Tables

1 The Need For Sustainability 1 The Current State of Design . . . . . . . . . 2 Sustainable Design Methodologies . . . . . . 3 The Cradle to Cradle Philosophy . . . . . . . 1.3.1 Rooted in Nature . . . . . . . . . . . 1.3.2 Cradle to Cradle Goals . . . . . . . . 1.3.3 Implementation . . . . . . . . . . . . 4 Document Outline . . . . . . . . . . . . . . . 1.4.1 Product Material Selection . . . . . . 1.4.2 Conscientious Manufacturing Design 1.4.3 Post Production . . . . . . . . . . . .

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2 Metal Alloys 1 Carbon Alloy Steels . . . . . . . . . . . . . 2.1.1 Material Properties . . . . . . . . . 2.1.2 Material Production and Recycling 2.1.3 Sustainability . . . . . . . . . . . . 2 Stainless Steels . . . . . . . . . . . . . . . . 2.2.1 Material Properties . . . . . . . . . 2.2.2 Material Production and Recycling 2.2.3 Sustainability . . . . . . . . . . . . 3 Tool & Die Steels . . . . . . . . . . . . . . 2.3.1 Material Properties . . . . . . . . . 2.3.2 Material Production and Recycling i

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CONTENTS 4

2.3.3 Sustainability . . . . . . . . . . . . Aluminum Alloys . . . . . . . . . . . . . . . 2.4.1 Material Properties . . . . . . . . . 2.4.2 Material Production and Recycling 2.4.3 Sustainability . . . . . . . . . . . . Titanium . . . . . . . . . . . . . . . . . . . 2.5.1 Material Properties . . . . . . . . . 2.5.2 Material Production and Recycling 2.5.3 Sustainability . . . . . . . . . . . . Magnesium Alloys . . . . . . . . . . . . . . 2.6.1 Material Properties . . . . . . . . . 2.6.2 Sustainability . . . . . . . . . . . . Copper Alloys . . . . . . . . . . . . . . . . 2.7.1 Material Properties . . . . . . . . . 2.7.2 Sustainability . . . . . . . . . . . . Nickel . . . . . . . . . . . . . . . . . . . . . 2.8.1 Material Properties . . . . . . . . . 2.8.2 Sustainability . . . . . . . . . . . . Zinc . . . . . . . . . . . . . . . . . . . . . . 2.9.1 Material Properties . . . . . . . . . 2.9.2 Sustainability . . . . . . . . . . . .

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3 Plastics 1 Material Properties . . . . . . . . . . . . . . . . 3.1.1 Molecular Properties of Plastics . . . . . 3.1.2 Types of Plastics . . . . . . . . . . . . . 3.1.3 Properties of Plastics to Consider . . . . 2 Production . . . . . . . . . . . . . . . . . . . . . 3.2.1 Mechanical Creation of Plastic Products 3.2.2 Chemical Creation of Plastics . . . . . . 3.2.3 Creation of Bioplastics . . . . . . . . . . 3 Lifetime . . . . . . . . . . . . . . . . . . . . . . . 3.3.1 Economics of Processing Plastics . . . . 4 Recycling . . . . . . . . . . . . . . . . . . . . . . 5 Sustainability . . . . . . . . . . . . . . . . . . . . 3.5.1 Sustainable Solutions . . . . . . . . . . . 3.5.2 Problems with Plastics . . . . . . . . . .

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CONTENTS 3.5.3 The Plastic Scorecard

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4 Ceramics, Composites and Elastomers 1 Ceramics . . . . . . . . . . . . . . . . . . . 4.1.1 Material Properties . . . . . . . . . 4.1.2 Material Production and Recycling 4.1.3 Sustainability . . . . . . . . . . . . 2 Composites . . . . . . . . . . . . . . . . . . 4.2.1 Material Properties . . . . . . . . . 4.2.2 Material Production and Recycling 4.2.3 Sustainability . . . . . . . . . . . . 3 Elastomers . . . . . . . . . . . . . . . . . . 4.3.1 Material Properties . . . . . . . . . 4.3.2 Material Production and Recycling 4.3.3 Sustainability . . . . . . . . . . . .

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5 Machining and Tools 1 Guidelines to Streamline Machining Processes . . 2 Designing for Maximum Reusable Material . . . 5.2.1 Input Energy and Pollutant Production . 5.2.2 Plant and Machining Selection . . . . . . 3 Elimination and Recapturing of Waste . . . . . . 5.3.1 Inventory . . . . . . . . . . . . . . . . . 5.3.2 Over Production . . . . . . . . . . . . . 5.3.3 Over Processing . . . . . . . . . . . . . . 5.3.4 Recovery of Materials and Energy . . . . 4 Proper Procedures for Machining . . . . . . . . . 6 Sustainability in Production 1 Sustainability in Different Production Methods 6.1.1 Plastics . . . . . . . . . . . . . . . . . 6.1.2 Metals . . . . . . . . . . . . . . . . . . 2 Six Sigma . . . . . . . . . . . . . . . . . . . . . 6.2.1 Origins of Six Sigma . . . . . . . . . . 6.2.2 Certification and Use of Six Sigma . . 3 Lean Production . . . . . . . . . . . . . . . . . 6.3.1 A Brief History . . . . . . . . . . . . . 6.3.2 Implementation of Lean Production . . iii

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CONTENTS 4

Demand Forecasting Management and Inventory Management . . . . . . . . . 6.4.1 Demand Management and Forecasting . . . . . . . . . . . . . . . . . 6.4.2 Inventory Management . . . . . . . . . . . . . . . . . . . . . . . . . . Manufacturing Conscientious Design - Examples of Conscientious Production 6.5.1 Suncor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.5.2 Rio Tinto Alcan . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.5.3 S.C. Johnson . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.5.4 General Electric . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

7 Assembly and Disassembly 1 Common Fasteners . . . . . . . . . . . . . . . . . 2 Built In Fasteners . . . . . . . . . . . . . . . . . 3 Temporary Fasteners . . . . . . . . . . . . . . . . 4 Adhesives . . . . . . . . . . . . . . . . . . . . . . 5 Designed Assembly Connector Concepts . . . . . 7.5.1 Mistake-Proof Assembly Parts . . . . . . 7.5.2 Oriented Parts and Oriented Handling . 7.5.3 Ease and Efficiency of Assembly Design . 7.5.4 Modular Parts within Products . . . . .

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8 Packaging 1 General Guidelines for Sustainable Package Design 8.1.1 Sustainable Packaging Metrics . . . . . . . 8.1.2 Product Safety . . . . . . . . . . . . . . . 8.1.3 Distribution . . . . . . . . . . . . . . . . . 8.1.4 Resource Recovery . . . . . . . . . . . . . 2 Food and Beverage Packaging . . . . . . . . . . . . 8.2.1 Beverages . . . . . . . . . . . . . . . . . . 8.2.2 Dairy and Cheese . . . . . . . . . . . . . . 8.2.3 Dry Foods and Snacks . . . . . . . . . . . 8.2.4 Meats and Seafood . . . . . . . . . . . . . 8.2.5 Produce . . . . . . . . . . . . . . . . . . . 8.2.6 Ready Meals . . . . . . . . . . . . . . . . 8.2.7 Food Service . . . . . . . . . . . . . . . . . 3 Consumables Packaging . . . . . . . . . . . . . . . 8.3.1 Excess Packaging . . . . . . . . . . . . . . 8.3.2 Change in Design . . . . . . . . . . . . . . 8.3.3 Reuse . . . . . . . . . . . . . . . . . . . . iv

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CONTENTS 8.3.4 Customer Focus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107 9 Waste Management 1 Office and Human Sustainability . . . . . . . . . . . . . . 9.1.1 Paper Management . . . . . . . . . . . . . . . . . 9.1.2 Electronic, Medical, and Chemical Waste . . . . . 9.1.3 Food Waste . . . . . . . . . . . . . . . . . . . . . 2 Post Product Life Sustainability . . . . . . . . . . . . . . 9.2.1 Recycling at End of Life . . . . . . . . . . . . . . 9.2.2 Recycling Materials . . . . . . . . . . . . . . . . . 9.2.3 Non-toxic Materials . . . . . . . . . . . . . . . . . 9.2.4 Frequently Discarded Components . . . . . . . . 3 Bulk Waste Management . . . . . . . . . . . . . . . . . . 9.3.1 Manufacturing Waste Management . . . . . . . . 9.3.2 Construction and Demolition Waste Management 4 Big Picture . . . . . . . . . . . . . . . . . . . . . . . . . . 9.4.1 Waste as a Source of Energy . . . . . . . . . . . . 9.4.2 Waste Generation Monitoring Methods . . . . . . 10 Green Label Benchmarks and Evaluation 1 Information Companies must Provide . . . . . . . . . 10.1.1 Introduction . . . . . . . . . . . . . . . . . . . 10.1.2 Energy Used in Production of Each Product . 10.1.3 Carbon Footprint Left By the Product . . . . 10.1.4 Percentage of Recyclable Content . . . . . . . 10.1.5 List of Materials Used . . . . . . . . . . . . . 10.1.6 Waste Created By Each Product . . . . . . . 10.1.7 Conclusion . . . . . . . . . . . . . . . . . . . . 2 Product Life Requirements . . . . . . . . . . . . . . . 10.2.1 Product Life Considerations . . . . . . . . . . 10.2.2 Setting the Standard . . . . . . . . . . . . . . 3 Examples of Selected Lifespan Requirements . . . . . . 10.3.1 Example: Compact Fluorescent Lamp (CFL) . 10.3.2 Lifetime Performance Standard Examples . . 4 Maximum Energy Consumption during Production . . 10.4.1 Measuring energy consumption . . . . . . . . 10.4.2 Production . . . . . . . . . . . . . . . . . . . 10.4.3 Implementing limitations . . . . . . . . . . . . v

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CONTENTS 5

Emissions Levels During Production . . . . . . 10.5.1 Carbon Monoxide . . . . . . . . . . . . 10.5.2 Lead . . . . . . . . . . . . . . . . . . . 10.5.3 Ozone . . . . . . . . . . . . . . . . . . 10.5.4 Particulate Matter . . . . . . . . . . . 10.5.5 Nitrogen Dioxide . . . . . . . . . . . . 10.5.6 Sulfur Dioxide . . . . . . . . . . . . . . Green Standards for Sources of Raw Materials . 10.6.1 Ecosystems in Danger . . . . . . . . . 10.6.2 Standards of Protection . . . . . . . .

Bibliography

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List of Figures 1.1 1.2 1.3 1.4

Total aluminum can waste vs. time [5] . . . . . . . Typical material composition of trash . . . . . . . Ideal waste distribution with perfect recycling and Cyclic nature of cradle to cradle design [9] . . . . .

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2.1 2.2

Recyclable aluminum scrap [23] . . . . . . . . . . . . . . . . . . . . . . . . . . Titanium sponge and rounds stock [24] . . . . . . . . . . . . . . . . . . . . . .

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3.1 3.2 3.3 3.4 3.5 3.6 3.7

Extrusion [36] . . . . . . . . . . . . . . . Injection molding [37] . . . . . . . . . . Blow molding [38] . . . . . . . . . . . . Rotational molding [39] . . . . . . . . . Effects of chemicals on plastic wear . . Cost comparison of material processing Plastic scorecard example [47] . . . . . .

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4.1 4.2 4.3

RWTH ceramics lifetime testing [50] . . . . . . . . . . . . . . . . . . . . . . . Recycling versus cost for various materials [52] . . . . . . . . . . . . . . . . . . Hybrid composite material [56] . . . . . . . . . . . . . . . . . . . . . . . . . .

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5.1

Water Cooled and Lubricated Mill [71] . . . . . . . . . . . . . . . . . . . . . .

6.1 6.2

ERP System Function Map [90] . . . . . . . . . . . . . . . . . . . . . . . . . . Forms of Inventory [91] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

77 78

7.1 7.2 7.3

Different snap fit types for disassembly [98] . . . . . . . . . . . . . . . . . . . These wood circular symmetric pins can be installed with any rotation [108] . These asymmetrical computer ports do not allow incorrect connectors or incorrect orientation of the connetor which removes ambiguity [109] . . . . . . . Notches and hole pattern angles only permit one orientation for assembly [110]

84 87

7.4

vii

. . . . . . .

. . . . . . . . . . . . . . composting . . . . . . .

. . . . . . .

. . . .

. . . . . . .

. . . .

. . . . . . .

. . . .

. . . . . . .

. . . .

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. . . .

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. . . .

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88 88

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LIST OF FIGURES 7.5 7.6

Table top utilizing incremental pins to keep table level while offering varying height options [111] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . This specific spacer was used to allow for multiple motor sizes to fit within the same case molding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

89 91

8.1 8.2 8.3 8.4 8.5 8.6 8.7

B¨ar & Knell lamps [113] . . . . Harley Davidson reusable steel Waterproof envelope [114] . . . Air-cushioned packaging [114] . Optimum pack design . . . . . Three levels of packaging . . . Packaging life cycles [112] . . .

. . . . . . . . packaging [114] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . .

. 95 . 96 . 96 . 97 . 98 . 99 . 101

9.1 9.2 9.3 9.4 9.5 9.6

Fujitsu ScanSnap scanner [136] Epson WorkForce scanner [136] Recycling computers [137] . . . EnergyStar logo [140] . . . . . . Diagram of incineration [149] . Diagram of Gasification [150] .

. . . . . .

111 112 113 114 119 120

10.1 Energy consumption from Annual Energy Review [156] . . . . . . . . . . . . . 130 10.2 End-use sector total consumption and shares from Annual Energy Review [156] 131 10.3 Global view of the world’s most endangered forests [157] . . . . . . . . . . . . 134

viii

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List of Tables 1.1

2.1 2.2 2.3 2.4 2.5 2.6 2.7

Human and ecological health criteria for MBDCâ&#x20AC;&#x2122;s materials assessment protocol [9] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Quick-reference table of sustainable metals . . . . . . . . . . . . . . . . . . . Steel properties [12] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Properties of Various Aluminum Alloys at Room Temperature [12] . . . . . . Properties and typical forms of various wrought magnesium alloys . . . . . . Properties and typical applications of various wrought copper and brasses [27] Properties and typical applications of various wrought bronzes [27] . . . . . . Properties and typical applications of various nickel alloys (all alloy names are trade names) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

14 17 21 25 27 28

3.1

Densities of common plastics [44] . . . . . . . . . . . . . . . . . . . . . . . . .

4.1 4.2

Material properties of ceramics [49] . . . . . . . . . . . . . . . . . . . . . . . . Basic properties of elastomers [62] . . . . . . . . . . . . . . . . . . . . . . . . .

51 58

5.1 5.2

Sector energy consumption and energy intensity in 2002 [68] . . . . . . . . . . 64 Energy-related CAP emissions by sector in 2002 (units TPY: tons per year) [68] 65

6.1 6.2

Energy Consumption for different Steel Production Methods (GJ/ton product) [78] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Six Sigma Levels of Certification [81] . . . . . . . . . . . . . . . . . . . . . . .

9.1 9.2

List of recyclable materials adapted from EPA [141] . . . . . . . . . . . . . . . 115 Sustainable Benefits of Waste Processing Methods [145] . . . . . . . . . . . . . 117

72 74

10.1 Product Label Template . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 126 10.2 Qualified CFL Warranty and Lifetime Statements Chart from Energy Star . 128 10.3 Stains and finishes lifespan requirements from Green Seal . . . . . . . . . . . 129

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Chapter 1 The Need For Sustainability Currently, the world is facing a crisis of design. Civilization was blessed with a generous, but finite amount of resources which man has found innumerable ways to convert into tools that increase health and happiness. While this is certainly to be celebrated, the crisis lies in the attitude with which these resources have been employed. What was at first seemingly endless is now clearly finite as more and more of the world attains a higher standard of living and adopts the consumerism that accompanies it. What is needed is a change in attitude, a different approach to design in which not only form and function are considered, but also the greater impact of design decisions, the way in which products affect not only their immediate consumer, but also the quality of life of others, the availability of resources to future generations, and the overall health of the planet. By picking this handbook up, you are taking a first step toward easing this crisis and moving toward a newer, more sustainable method of design. While much of the content in this handbook is far from dramatic, it provides you, the designer, with the necessary information so that reasoned and equitable decisions can be made regarding the environmental impact of the engineering profession. Seemingly minor choices like material selection and assembly techniques have the power in aggregate to push society further down the path of resource exhaustion or to chart a new course of sustainable, harmonious resource use. So while replacing internal fasteners with snap fits or deliberately choosing recyclable materials may seem unlikely to have a significant impact on the global environment, collectively, these decisions add up. By educating a new crop of engineers and designers to make environmentally responsible decisions, a sustainable approach to product development will allow society to make the best use of its resources in the present and to maximize their use for generations to come. This chapter begins by examining just how dire the current state of design and resource management is, identifying the moral imperative that engineers have to change their thinking and develop a more sustainable process. Next, several existing approaches to sustainable design are considered, summarizing some of the work that has already been undertaken. Then, the philosophy of cradle-to-cradle design, the approach applied in this handbook, is explained, stressing the importance of examining a productâ&#x20AC;&#x2122;s entire life cycle, from the harvesting of resources to eventual disposal. Lastly, a brief summary of this documentâ&#x20AC;&#x2122;s contents is provided along with some suggestions as to how this text is intended to be used. 2

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CHAPTER 1. THE NEED FOR SUSTAINABILITY

The Current State of Design As discussed above, the way in which society views and utilizes natural resources is rapidly developing into a crisis. As the consumption of energy and consumer goods continues to increase in the developed world and an ever-growing portion of the globe adopts Western-style consumer practices, the sheer scale of production and the amount of resources being used creates the potential for vast environmental damage. According to the United States Environmental Protection Agency, “In the past 50 years, humans have consumed more resources than in all previous history” [1] . But increased consumption by itself is not the problem; the real damage is done in the way that this incredible consumption is achieved. The Natural Resources Defense Council reports that mankind collectively adds six to eight billion tons of carbon to the atmosphere each year by burning fossil fuels and destroying forests [2] . Not only does this cause global warming that could raise the earth’s temperature by up to 10 ◦ F by 2050, but also over 80 % of the world’s forests are now gone because of man’s impact [3] ! Turning to the seas, millions of pounds of toxic chemicals like lead, mercury and pesticides pour into waterways each year, contaminating wildlife, seafood and drinking water. The damage has been so extensive that more than 40 % of fresh water is no longer drinkable [2] . It is clear that current agricultural, industrial and consumer processes are not only consuming vast amounts of natural resources, they are also resulting in the unintentional destruction of additional resources. And the impact extends to wildlife, as well: currently 50 to 100 species of plants and animals become extinct every day because of a loss of habitat and detrimental human influences [4] .

Figure 1.1: Total aluminum can waste vs. time [5] But the process of production is not the only factor contributing to this crisis; the creation of waste, the disposal of consumer goods, and other end-of-life issues are also creating major environmental problems. Excessive packaging for consumer products accounts for 30 % of what Americans throw away every day, made worse by a low recycling rate [2] . For 3

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CHAPTER 1. THE NEED FOR SUSTAINABILITY example, airlines alone throw away enough aluminum cans each year to build 57 brand new Boeing 747s [5] . In total over the last 30 years, Americans have thrown away over 900 billion cans, worth over $25 billion, and this number is increasing annually as seen in Figure 1.1 [6] . And it is not just cans alone that are improperly wasted: 25 % of what Americans throw away are organic products that could be composted instead of thrown in the landfill [7] . A more detailed breakdown of exactly what is going into the nationâ&#x20AC;&#x2122;s landfills can be seen in Figure 1.2.

Figure 1.2: Typical material composition of trash This figure can be compared to Rubbish Boys Disposal Serviceâ&#x20AC;&#x2122;s ideal waste destination distribution (see Figure 1.3) for the waste identified in Figure 1.2. Only 40 % of waste should be destined for landfills, although the percentage observed is much higher. Many of these problems are rooted in the way products are designed. Of all things people buy, 99 % are not in use after 6 months [3] . This can be partially attributed to the fact that designers create products to fail so they can make more money by selling them again. An obvious example would be portable consumer electronics like the iPod and cellphones. Manufacturers put a battery in these devices that lasts roughly 2 years. After 2 years the iPod is out of warranty, and Apple does not offer a service to replace the battery. They expect the consumer to buy a new and improved version rather than continue with their still functional devices. Cell phone distributors employ a similar scheme, offering newer free phones with a new 2-year contract. These practices are extremely detrimental to the environment as the old devices still function; they only need replacement batteries or a battery that will actually last as long as the product will. Clearly man is not living in harmony with the environment, and our natural resources cannot continue to support us at the rate at which we are abusing them. This is why it is critical to turn to the public, and, even more importantly, to the people who design and manufacture consumer products to address the issue of sustainability before it is too late. Because of the rapidly fading nature of our natural resources, the growing problem of storing waste, and the flaws inherent in the way products are designed, there is a moral imperative to improve the design of consumer goods and more generally to transform the way engineers 4

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CHAPTER 1. THE NEED FOR SUSTAINABILITY

Figure 1.3: Ideal waste distribution with perfect recycling and composting approach design. The environmental impacts of each design decision must be given due consideration just as the functional and aesthetic effects of design choices are evaluated. While it may not be possible to radically alter the approach to design immediately, it is critical that steps toward change are undertaken now.

Sustainable Design Methodologies Sustainable design is a design method that strives to minimize the negative impact of human activities on the environment. Its goal is to conserve energy and natural resources as well as preserve habitats by mimicking and taking advantage of the environment as in the utilization of sun and wind energy. Sustainable design can include measures such as reuse or recycling or larger measures like the design of walk-only communities or efficient public transportation. Formal systems and design methodologies for sustainability exist in a variety of fields such as agriculture, architecture and graphic design. Architecture possesses by far the most fully developed set of “green” design guidelines. LEED Certification of “green buildings” is a prime example of architecture’s documented methodologies. To qualify as a sustainable design, buildings must include features such as green roofs and natural ventilation, and a governing body exists to determine whether a structure satisfies the multiple tiers of LEED requirements [8] . Unfortunately, this program is limited to building applications, and there is no broadly accepted equivalent for mechanical design. While there are few formal guidelines for sustainable mechanical design, considerable work is being done in the area. The American Society of Mechanical Engineers holds annual conferences on sustainability in design, and considerable literature has been produced on 5

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CHAPTER 1. THE NEED FOR SUSTAINABILITY the subject. One of the leading discussions of the topic is William McDonough and Michael Braungartâ&#x20AC;&#x2122;s book Cradle to Cradle. Cradle to cradle offers a holistic approach to design which examines a productâ&#x20AC;&#x2122;s life from resource harvest through disposal. This handbook seeks to present a technical description of the cradle to cradle philosophy and its applications to mechanical design.

The Cradle to Cradle Philosophy The idea of cradle to cradle design was created in the 1970s by Walter R. Stahel. It was not until 2002 with the publication of the book, Cradle to Cradle by William McDonough and Michael Braungart, that cradle to cradle design was effectively described. The book also provided ways to implement their methods.

1.3.1

Rooted in Nature

Cradle to cradle design is a biometric approach to design. Its goal is to imitate nature by making manufacturing processes similar to natural processes, as shown in Figure 1.4. Nature operates in a cyclic manner. Plants provide food for animals, whose wastes provide nutrients for the soil which feeds the plants. There are no wastes. Most design involves a linear process where manufacturing creates a product which is purchased by a customer and is then thrown out as waste, and remains in a landfill. Cradle to cradle design can be used in a variety of areas such as industrial design, manufacturing, buildings, economics, and social systems. The principles of cradle to cradle are based on parallel principles observed in nature: Waste Equals Food The first key principle taken from nature is the concept that waste equals food. In a cradleto-cradle system, waste really is not waste at all, but rather, it is merely a reduction to the building blocks of the original product. In order to make this a reality in mechanical design, designers and engineers must perform scientific testing to choose materials that are fundamentally safe (for both humans and the environment) and sustaining in order to create a closed-loop material flow [9] . These building block materials can be either biological or technical (synthetic.) Biological nutrients, like textiles and packaging, are those made from natural fibers that can biodegrade safely and restore soil after use [9] . Technical nutrients, like carpet yarns, are those made from synthetics. They can be continually depolymerized and repolymerized and provide more complex elements that are reusable indefinitely.

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CHAPTER 1. THE NEED FOR SUSTAINABILITY

Figure 1.4: Cyclic nature of cradle to cradle design [9] Use Current Solar Income In order for cradle-to-cradle systems to be sustainable and essentially waste-free they must be fueled by a clean, safe, and renewable source of energy. From the natural world, it is obvious to see that solar and wind energy are the most innate sources of energy. The utilization of solar energy could include both direct solar energy collection and just making more effective use of the sun as a natural light, also known as daylighting. Celebrate Diversity In nature, every organism finds a way to adapt to its environment. Every organism is unique and it is this uniqueness that helps it to effectively survive in its natural habitat. Conversely, modern engineering largely conforms to the idea and championing of the standardized onesize-fits-all products for everyone in every environment in every situation. However, as proven in nature, embracing and celebrating diversity and distinctiveness is both more effective and sustainable. The more characteristics the environment and the individual can be considered and exploited, the more efficient the design.

1.3.2

Cradle to Cradle Goals

Products can also be cradle to cradle certified. The certification program focuses on, â&#x20AC;&#x153;using safe materials that can be disassembled and recycled as technical nutrients or composted as 7

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CHAPTER 1. THE NEED FOR SUSTAINABILITY biological nutrients” [9] . The criteria for certification are material health, material reutilization, renewable energy use, water stewardship, and social responsibility. A major concern is the safety of the materials used in products. Cradle to cradle design ensures that only materials that are safe and healthy for humans and the environment are used. In nature, even the dangerous “materials” such as animal venom, which in small doses can be useful, are nowhere near as damaging as man-made materials such as nuclear waste, which can remain dangerous for years. The material health of a product is graded based on a color coded system where green mean there is little to no risk, yellow is moderate risk, red is high risk, and grey means the product cannot be categorized. The table below indicates how materials are evaluated for safety:

Table 1.1: Human and ecological health criteria for MBDC’s materials assessment protocol [9] Human Health Criteria

Ecological Health Criteria

Carcinogenicity Teratogenicity Reproductive Toxicity Mutagenicity Endocrine Disruption Acute Toxicity Chronic Toxicity Irritation of Skin/Mucous Membranes Sensitization Other Relevant Data

Algae Toxicity Bioaccumulation Climatic Relevance Content of Halogenated Organic Compounds Daphnia Toxicity Fish Toxicity Heavy Metal Content Persistence/Biodegradation Other

Material reutilization involves eliminating waste by recycling product for future use. In effect, a product should have multiple life cycles, where the end of one life cycle is the beginning of another life cycle. The maker of the product should also have a plan to make sure the product is actually recycled and not just thrown into a landfill. The product is given a material reutilization score during certification that determines the level of certification. Cradle to cradle design also encourages the use of renewable energy. These forms of energy include solar, wind, and geothermal energy. Renewable energy should be used in the manufacturing and assembly of the product. Higher levels of certification require that at least 50 % of the energy used for design and assembly comes from solar sources. Water stewardship means any water used in the manufacturing process of the product must not be polluted. It must leave the process just as clean as it was when it entered the process or cleaner if possible. When the product is manufactured, the water supply should not be depleted, which means the lake or river should not become smaller in size over time. One of the key characteristics of cradle to cradle design is social responsibility. Products should be made in ways that respect the health, safety, and rights of others and the environment. When a product is made, it should be made in an ethical way. Companies are even encouraged to have a third party assess their manufacturing processes to insure they are in compliance with the social responsibility aspect of cradle to cradle certification. 8

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CHAPTER 1. THE NEED FOR SUSTAINABILITY

1.3.3

Implementation

In order to implement cradle to cradle design, existing products should be evaluated. Their components need to be listed and broken down into their base chemicals. All of the chemicals need to be categorized based on their health hazards. The chemicals need to be evaluated for their human and environmental impacts throughout their entire life cycles. Then they need to be evaluated for their renewability and recyclability. Once all the evaluations of the product are complete changes should be made to the manufacturing of the product based on the data. The high risk chemicals listed should immediately be taken out of the product and replaced with safer chemicals. The medium risk chemicals should eventually be taken out of the product and replaced with safer chemicals. The low/no risk chemicals should be kept in the product. The manufacturer should find a way to make the product fully recyclable or biodegradable and to make the product using only renewable energy. Most likely, implementation of cradle to cradle design will take time. The first attempt at cradle to cradle will probably not remotely resemble the final attempt. In order to fully realize cradle to cradle design, long term goals should be set by the manufacturer and met over time. Sometimes, the manufacturers will have to wait until market conditions, such as material prices, are favorable in order to make cradle to cradle design cost effective. The key part is making the decision to implement cradle to cradle design and beginning to make the necessary changes in the manufacturing process.

Document Outline The intended purpose of this document is to provide a design resource for engineers that addresses sustainable design and the implementation of cradle to cradle design philosophy. This document will provide guidelines for mechanical engineers to aid in the development of sustainable products and systems. It is usable both as a textbook for student use and as a reference that can be called upon as needed in the workplace. The Green Label Benchmark is introduced, and the standards for are explained. Information necessary for a product to receive the green label is laid out, as well as certain areas of standard requirements, such as product life, energy usage, lifetime performance, and emission levels during production. Several pollutants are considered, including carbon monoxide, lead, and nitrogen dioxide. Consideration is given to the sites that raw materials may be taken from, and potential ecological troubles that could follow. Decision processes particularly important to sustainability include the selection of product material, the consideration given to the manufacturing of the product, and the consideration given to relevant post-production characteristics. These are the topics that will be given the greatest focus in this document.

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CHAPTER 1. THE NEED FOR SUSTAINABILITY

1.4.1

Product Material Selection

Potential product materials include metals, plastics, and ceramics, each of which raises unique sustainability challenges. The individual properties of a variety of materials are considered, and the sustainability implications of each are evaluated. Several metals and metal alloys are considered, including stainless steels, aluminum alloys, copper alloys, and zinc, among others. The use of plastics is discussed, and differing types of plastics such as PVC and Polycarbonate are evaluated, along with discussion of material use and production processes such as extrusion and injection molding. In addition, several other types of engineering materials, such as ceramics, composites, and elastomers, are also addressed. The material properties and sustainability characteristics of these materials are then assessed.

1.4.2

Conscientious Manufacturing Design

Manufacturing characteristics to be considered for effective sustainable design include the tools and machinery used in fabrication of a product, the assembly process, and the production system as a whole. Streamlining of the machining process is a topic of discussion, as well as consideration of reusable material, minimal waste byproducts, and proper machining procedures. The importance of the production process is emphasized, and production methods such as Six Sigma application, lean production strategies, demand forecasting, and inventory management can all prove useful as sustainability strategies. Several examples of conscientious production processes that have been successfully implemented are then presented. Finally, there is a discussion on accounting for assembly and disassembly in the design process. A variety of assembly methods are discussed and evaluated, including screws, washers, rivets, snap fits, press fits, welds, staples, and adhesives, such as glue or tape. Each assembly method is assessed and considered in the context of sustainable design, and recommendations are made on the importance of design for assembly, especially for sustainability.

1.4.3

Post Production

Finally, issues relevant to post production processing will be discussed, including the packaging of the product and the recyclability or disposability of the product. Waste disposal is considered, along with the difficulties of the disposal of electronic, medical, or chemical waste. Recyclability is a key issue in sustainable design, and is addressed, along with consideration given to to waste management and methods of waste disposal, such as incineration or gasification. In addition to waste disposal, another key post production issue is the packaging used on a product. Design guidelines are given to address topics such as reusability, recyclability, cost- effectiveness, and the goal of a closed-loop system. Separate guidelines are given for the packaging of food, beverages, or consumables.

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Chapter 2 Metal Alloys When designing to reduce negative impacts on the environment, it is important to have an understanding of available metal alloys and their properties. Metal products contribute considerably to the sustainable design movement. High recycled content, recyclability, fully developed distribution networks, and energy efficiency are all reasons to consider metal as a sustainable material choice when designing products of any class. In order to effectively utilize metals as a sustainable design choice, the designer must have a basic understanding of possible uses for each metal type and how often and effectively they are recycled. The following sections contain material property data and sustainability statistics for several of the most commonly used metals in consumer products. Quick-Reference Table Table 2.1 summarizes some of the key statistics that should be considered when deciding which metal to choose for a sustainable design application. A list of possible material choices for your product should be identified based off yield strength requirements, and then the final choice should be made by quantitatively comparing the corresponding sustainability statistics . Two of the most important factors that should be considered when making this decision are the energy required to produce the material, and the ease and practicality of recycling the material once the product has reached the end of its life. These somewhat abstract concepts of sustainability can be quantitatively defined by looking at how often each material is recycled and the amount of energy that is saved by recylcling it. Aluminum is one of the most sustainable metal choices because of its vast range of applications and the 95 % decrease in production energy. Copper is also a top contender because it is extensively recycled and it takes approximately 85 % less energy to produce recycled copper than it does to produce new copper from ore. As a rule of thumb, the majority of metal alloys are sustainable choices because of the prevalent recycling options available and the increased product lifetime achieved by using them. More general information about specific metal types can be found in the following sections.

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CHAPTER 2. METAL ALLOYS

Table 2.1: Quick-reference table of sustainable metals Metal

Life (years)

Recycled (%)

Energy Reduction (%)

Other Benefits (per ton recycled)

Carbon Steels

Stainless Steels

80-500

80-90

1100 kg Fe saved

Tooling Steels

500

1100 kg Fe saved

Aluminum

1-20

14 MWh saved

Titanium

> 500

Magnesium

Copper

85%

Zinc

Carbon Alloy Steels 2.1.1

Material Properties

Steel, an iron alloy with carbon content up to 2.1 %, is one of the most common materials available worldwide. The many classes of steel are generally distinguished by their alloying content, and the most popular of these is carbon steel, in which carbon is the main or only alloying element. Over 85 % of steel produced in the United States is carbon steel. Carbon steels are further classified by relative carbon content. Increasing the carbon content generally increases the strength of the steel, but lowers its ductility and its melting point. There are many production and treatment practices in the steelmaking process (notably heat treatment and deoxidation) intended to change the properties of the steel for a desired effect, but carbon content variations normally have a much greater effect on the mechanical properties. 1. Mild and Low-Carbon Steel: up to 0.3 % C • Common, inexpensive, and ductile. Often flat-rolled for use in automobile bodies and structural steel. 2. Medium-Carbon Steel: 0.3 % to 0.6 % C • Good resistance to wear; often used in axles, gears, and rails. 3. High-Carbon Steel: 0.6 % to 1.0 % C • Very strong yet brittle, responds well to heat treatment, and often used in springs and high-strength wires. 4. Ultrahigh-Carbon Steel: 1.0 % to 2.0 % C 14

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CHAPTER 2. METAL ALLOYS â&#x20AC;˘ Experimental alloys used in specialty products, often produced via powder metallurgy. Steel with above 2.1 % carbon content is instead considered cast iron. When steel is alloyed with any variety of non-carbon elements, it is considered alloy steel. The most common elements used as alloyants are manganese, nickel, molybdenum, and chromium. The use of these alloys is generally to affect the mechanical properties such as strength, hardness, hardenability, magnetism, or heat resistance. The sheer number of possible alloying combinations and concentrations allows specialized steels to be developed for many specific applications.

2.1.2

Material Production and Recycling

Since steel is one of the most easily recycled materials and is 100 % recyclable, modern steel production relies heavily on scrap steel, making approximately two-thirds of new steel from recycled material. An electric arc furnace is the most common secondary steelmaking process, in which the steel is melted for reuse. Electric arc furnaces allow production to use nearly 100 % scrap metal. By contrast, primary steelmaking with raw materials uses basic oxygen furnaces, a process that requires significantly more energy and resources per unit weight produced. In fact, one ton of steel recycled saves 1.5 tons of mined iron ore, 0.5 tons of coal, and 75 % in energy consumption [10] . Electric arc furnaces are additionally advantageous because they can be started and stopped quickly, whereas blast furnaces used in primary steelmaking are never shut down and are unable to vary production quantities according to demand. The Steel Recycling Institute (SRI) reported a 2009 overall steel recycling rate of 103 %. Recycling rates are calculated not as part of a whole, but as a ratio of influx of recyclable material to new production. Since this is calculated year-to-year it is inflated by recent economic and production trends, but overall rates have been approximately 70 % to 80 % over the last decade. More specific recycling rates show steel from automobiles at 106 %, structural steel at 97.5 %, and construction reinforcement steel at 70 % [11] .

2.1.3

Sustainability

Steel is infinitely recyclable, meaning it maintains its mechanical properties indefinitely. As such, recycling is such a large component of the steel industry because, unlike many other sustainable practices, it is financially beneficial to both the consumer and the supplier. Despite the many benefits and the efficiency of modern steel recycling, there are nevertheless some adverse effects. These notably include the production of slag, a byproduct of steel production due to impurities in the metal. This is part of the smelting process and is therefore present in both primary and secondary steelmaking. The progression of technology in steel production continues to refine alloys for use in specific cases. One method of reducing the environmental impact when using steel is to choose a stronger alloy, or one which has been treated, that allows for less metal to be used overall. This concept has been implemented in many industries and materials already

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CHAPTER 2. METAL ALLOYS from soft drink cans to automobile bodies to reduce the total weight of the product without sacrificing the integrity of the material.

Stainless Steels 2.2.1

Material Properties

Stainless steels, by definition, consist of metal that has been alloyed with a minimum of 10 % chromium by weight. The alloying of chromium with steel makes stainless steel highly corrosion resistant and gives it a shiny protective layer on the surface which reforms if scratched. In addition to being corrosion resistant, stainless steels are ductile and strong with ultimate tensile strengths up to 620 MPa and elongations of up to 60 % [12] . Stainless steels can be alloyed with other metals and a few common types of stainless steels are listed below. 1. Austenitic steels • Nonmagnetic and comparatively ductile 2. Ferritic steels • Magnetic with high chromium content 3. Martensitic steels • Comparatively strong, hard, and fatigue resistant at the expensive of corrosion resistance 4. Precipitation-hardening steels • Strong and ductile 5. Duplex-structure steels • Strong with good corrosion resistance properties Stainless steels have a projected life of 80 years to 550 years, depending on the use and type of the stainless steel selected, before pitting becomes a serious issue [13] . Stainless steels have a wide range of uses varying from nuts and bolts to fishing tackle and oil rig equipment [12] . For a summary of further material property data see Table 2.2.

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CHAPTER 2. METAL ALLOYS

Table 2.2: Steel properties [12]

AISI (UNS) 303 (S30300)

Ultimate Yield Tensile Strength Strength (MPa) (MPa) 550 to 620 240 to 260

Ductility (%EL) 50 to 53

304 (S30400)

565 to 620

240 to 290

55 to 60

316 (S31600)

550 to 590

210 to 290

55 to 60

410 (S41000)

480 to 520

240 to 310

25 to 35

416 (S41600)

480 to 520

275

20 to 30

Characteristics Applications

and

Typical

Screw-machine products, shafts, valves, bolts, bushings, and nuts; aircraft fittings; rivets; screws; studs. Chemical and food-processing equipment, brewing equipments, cryogenic vessels, gutters, down-spouts, and flashings High corrosion resistance and high creep strength. Chemical and pulp-handling equipment, photographic equipment, brandy vats, fertilizer parts, ketchupcooking kettles, and yeast tubs Machine parts, pump shafts, bolts, bushings, coal chutes, cutlery, fishing tackle, hardware, jet engine parts, mining machinery, rifle barrels, screws, and valves Aircraft fittings, bolts, nuts, fire extinguisher inserts, rivets and screws.

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CHAPTER 2. METAL ALLOYS

2.2.2

Material Production and Recycling

Stainless steel is obtained through the alloying of steel and chromium. Steel is obtained through the mining of iron. Mining and processing iron has traditional environmental impact issues and produces wastewater and hazardous air emissions [14] . Chromium is obtained through the mining of chromium ore, which is very abundant on Earth [15] . Stainless steel is claimed for recycling at two different stages of its lifecycle. It can be recycled as new scrap or old scrap. New scrap is reclaimed stainless steel from manufacturing processes and accounts for 35 % of the recycled material. Old scrap is composed of returned materials claimed from products at the end of their life and metal obtained through scrap brokers at landfills. This type of scrap accounts for 25 % of the recycled material. The remaining 40 % of the recycled material are additional raw materials and other recycled metals that are added to the recycling process [16] . When recycled, stainless steel is melted down, cast into ingots, and sometimes rolled so that it can be repurposed [17] .

2.2.3

Sustainability

In general, the production and life-cycle of stainless steels have a very low impact on the environment as they are easily and efficiently recycled. This makes stainless steels a very smart material choice for sustainable design. On average 60 % of the production of new stainless steel involves recycled materials, and stainless steels themselves are 100 % recyclable. In 2006, for example, 28 million tons of stainless steel was produced. In this process 14 million tons of recycled stainless steel and other metals were used. The only reason stainless steels are not composed of more than 60 % recycled materials is that historical consumption of the metal does not keep pace with current demand [16] . Currently, it is estimated that around 80 % to 90 % of stainless steels are recycled at the end of their life. [16] . Energy reduction by recycling is difficult to quantify because recycling is an integral part of the production of stainless steel. The production of new stainless steel always involves using recycled stainless steel [18] . Recycling 1 ton of stainless steel saves 1100 kg of iron ore, 630 kg of coal, and 55 kg of limestone [17] . In addition, stainless steel can be recycled indefinitely without losing any material properties [16] . For this reason they are considered environmentally friendly and are a highly recommended choice for a sustainable metal, especially when high strength properties are desired.

Tool & Die Steels 2.3.1

Material Properties

Tool and die steels are steels that are commonly used for manufacturing and production purposes. They have high strength, impact toughness, and wear resistance. There are many different types of tool and die steels and several are listed below. 18

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CHAPTER 2. METAL ALLOYS 1. High-speed steels • Molybdenum and tungsten type; often alloyed with other elements • Designed for use at high operating temperatures with high strength and hardness 2. Hot-work steels • Designed for elevated temperature use • Very high toughness, wear resistance, crack formation resistance 3. Cold-work steels • Designed for cold-working processes • High wear and crack formation resistance 4. Shock-resisting steels • Very high impact toughness Tool and die steels are often alloyed with molybdenum, tungsten, chromium, vanadium, and cobalt [12] .

2.3.2

Material Production and Recycling

Tool and die steels are carbon steels that are alloyed with other elements. Therefore the creation of tool and die steels are related to the creation of carbon steel. Carbon steel is produced using iron ore and carbon. Iron ore is in abundant supply on Earth and is obtained through mining. The overall production of carbon steel poses environmental threats including the production of wastewater and hazardous air emissions [14] . Recycling processes are similar to carbon steel recycling. Metals are collected from new and old scrap and are separated according to properties. They are then melted and formed into ingots through casting to be reused [19] . Typically tool and die steels are recycled through the use of an electric arc furnace [20] .

2.3.3

Sustainability

In high-speed steels, approximately 60 % to 70 % of newly produced metal is made of scrap [21] . Although they are alloyed with other materials, tool and die steels are made primarily of carbon steel. As such they share many of the same sustainability properties as carbon steel. Carbon steel is a very recyclable metal, although as always, the production phase causes harm to the environment because it involves the processing of iron ore. As mentioned previously, carbon steel is a very good choice for a sustainable material as it is easy to recycle and is in abundant supply. Recycling tool and die steels is especially important so that the alloyed materials contained within can be reused. These metals, such as tungsten and vanadium are relatively scarce and difficult to obtain, so recycling is both 19

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CHAPTER 2. METAL ALLOYS economical and important to saving natural resources [17] . Recycling carbon steel uses 75 % less energy than creating new carbon steel [19] . Therefore, recycling tool and die steels saves even more energy because the difficult to obtain alloys are already present. When tool and die steels are needed there is little choice in sustainability. What is more important is recycling tool and die steels at the end of their usable life.

Aluminum Alloys 2.4.1

Material Properties

Aluminum is one of the most commonly used non-ferrous materials in manufacturing. This is due to its high strength-to-weight ratio, good corrosion resistance, high thermal and electrical conductivity, nontoxicity, appearance, and its formability and machinability. In addition, aluminum is nonmagnetic, which in some applications is beneficial. There is a wide range of aluminum alloys, each with distinct properties. There are two main types of aluminum alloys: â&#x20AC;˘ Those hardenable by heat treatment (designated by the letter T, e.g. Al 6061-T6) â&#x20AC;˘ Those hardenable by cold working (designated by the letter H, e.g. Al 5052-H34). Additionally, aluminum may be annealed and this is designated by the letter O. Basic properties for various aluminum alloys can be found in Table 2.3. Aluminum is formed via rolling, extrusion, drawing, and forging and can be machined and welded. Due to its versatility, aluminum is used in a wide range of products. A few products that are made of aluminum alloys are aircraft and automobile components, beverage cans, foil, and sporting equipment such as baseball bats [12] .

2.4.2

Material Production and Recycling

Aluminum is produced through an electometallurgical process; this energy-intensive process makes recycling even more appealing. To obtain aluminum, bauxite ore is mined and refined into the oxide, alumina. Alumina, electricity, and cryolite, a molten electrolyte, are combined in a cell and as a result, molten aluminum metal and carbon dioxide are produced. The molten metal is cast into ingots which may then be used for various manufacturing processes such as castings or extrusions. The ingots may also be shaped into mill products such as sheets, plates, bars, and round stocks which may be processed further by a customer in the future [22] . As is the case for other non-ferrous metals, a general outline of the recycling process for aluminum is as follows: (1) bale the material into a large block (2) shear the material into manageable sizes (3) separate ferrous and non-ferrous metals using a rotating magnetic drum, and (4) melt the non-ferrous metal, pour into a cast, and shape into an ingot [19] . More 20

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CHAPTER 2. METAL ALLOYS

Table 2.3: Properties of Various Aluminum Alloys at Room Temperature [12] Alloy (UNS)

Temper

1100 (A91100) 1100 1350 (A91350) 1350 2024 (A92024) 2024 3003 (A93003) 3003 5052 (A95052) 5052 6061 (A96061) 6061 7075 (A97075) 7075 8090

O H14 O H19 O T4 O H14 O H34 O T6 O T6 T8X

Ultimate Tensile Strength (MPa) 90 125 85 185 190 470 110 150 190 260 125 310 230 570 480

Yield Strength (MPa)

Ductility (%EL)

35 120 30 165 75 325 40 145 90 215 55 275 105 500 400

35 to 45 9 to 20 23 1.5 20 to 22 19 to 20 30 to 40 8 to 16 25 to 30 10 to 24 25 to 30 12 to 17 16 to 17 11 4 to 5

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CHAPTER 2. METAL ALLOYS specifically for aluminum, however, depending on the type to be recycled and its intended secondary purpose, one of the following processes may be completed [22] : • Used Beverage Container (UBC) Processing: Old aluminum cans and scrap from the can-making process are recycled into new can sheet. • Secondary Specification Aluminum Alloys: Scrap from various sources is used to make an alloyed ingot to the customer’s specifications. • Remelt Secondary Ingot (RSI): Aluminum scrap is melted down and formed into an ingot without a specific chemical composition. • Deoxidation ingot production: Aluminum scrap is used to form various shapes that are used for steel deoxidizing in the steel-making process. • Dross processing: Aluminum is collected either mechanically or chemically from the dross that forms during melting processes. This aluminum is returned to the customer either as molten metal or a RSI.

2.4.3

Sustainability

The biggest environmental concern for aluminum producers is the perflourocarboon (PFC) emission from smelting. Recycling aluminum is important not only because of the reduction of PFC emissions but also for the considerably less energy used to recycle scrap rather than produce new aluminum. There are many benefits to using recycled aluminum. First of all, by recycling, 95 % less energy is used than by producing aluminum from raw materials. By recycling one ton of aluminum, the following are saved [19] : • • • • •

8 tons of bauxite (an aluminum ore, the main source of aluminum) 14,000 kWh of energy 40 barrels of oil 251 kJ of energy 7.6 cubic meters of landfill

The environmental impact at the end of life for aluminum products is fairly low due to the prevalence and ease of recycling the material. Figure 2.1 shows aluminum scrap ready for recycling. From automobiles to beverage cans, there is a high rate of recycling (90 % and 57 % in the US respectively) of aluminum throughout the wide spectrum of products it is used in [22] . According to the Bureau for International Recyling, “of an estimated total of 700 million tonnes(sic) of aluminium produced since commercial manufacturing began in the 1880s, about 75 % of this is still being used as secondary raw material today.” In addition, 63 % of all aluminum beverage cans made are recycled worldwide, making it the most recycled container [19] . Aluminum and its alloys are very durable due to their good mechanical and chemical properties. As a result, the material’s lifetime greatly depends on its use. The aluminum found in an automobile will have a considerably different lifetime (e.g. years) than a beverage can (e.g. weeks to months).

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CHAPTER 2. METAL ALLOYS

Figure 2.1: Recyclable aluminum scrap [23]

Titanium 2.5.1

Material Properties

Titaniumâ&#x20AC;&#x2122;s use in commercial products began relatively recently (circa 1950s). Due to its high strength-to-weight ratio and good corrosion resistance at room and elevated temperatures, it is commonly used in aircraft, racing cars, and marine craft. In addition, titanium is bio-compatible, making it very useful in medical devices such as orthopaedic implants. Alloys are available in either powder or wrought forms. There are several different titanium alloys with varying mechanical properties, and their yield strengths, in fact, vary from 95 MPa to 1210 MPa. It can be formed, machined, and joined. Care must be taken during manufacturing to ensure that there is no surface contamination by hydrogen, oxygen, or nitrogen. This surface contamination could have a negative effect on mechanical properties [12] .

2.5.2

Material Production and Recycling

Producing titanium is an expensive process. The cost of production is a limiting factor in its popularity when compared to other materials. Titanium ingots are traditionally produced using vacuum arc remelting (VAR). More recently, cold-heart melting (CHM) and plasmaarc melting (PAM) have also been used due to their ability to remove high density inclusions. Titanium production is expensive due to the use of these melting processes. The following general steps are taken to turn titanium ore into an ingot ready for further processing: (1) reduce titanium ore to form an impure porous form of titanium metal (titanium sponge) (2) purify the sponge (3) melt the sponge or the sponge and alloy elements to form an ingot.

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CHAPTER 2. METAL ALLOYS

Figure 2.2: Titanium sponge and rounds stock [24]

The ingots can be made into sheets, bars, plates, or round stock as needed [25] . For example, on the left of Figure 2.2 is titanium sponge, and on the right, titanium round stock is shown. As is typical for non-ferrous metals, titanium is recycled by melting the titanium scrap. All types of scrap can be remelted. Prior to remelting the scrap, however, it must be cleaned and all surface scales must be removed in order to avoid defects in the ingot being produced [25] .

2.5.3

Sustainability

The durability of titanium greatly depends on the processing that it is subjected to. However, when titanium is made well it can have a considerably long life given its excellent corrosion resistance and strength [25] . Although there is a considerable amount of titanium scrap produced during the production of titanium components, typically little of it is recycled and reformed into titanium ingots. In fact, only around 5 % of titanium ingot production comes from old scrap [26]

Magnesium Alloys 2.6.1

Material Properties

Magnesium is the lightest engineering metal available; its alloys are used in structural and nonstructural applications where weight is of primary importance. Magnesium is also an alloying element in various nonferrous metals. â&#x20AC;˘ Properties: light weight, good vibration-damping characteristics, high strength-toweight ratios 24

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CHAPTER 2. METAL ALLOYS • Available Forms: Because it is not sufficiently strong in its pure form, magnesium is alloyed with various elements (see Table 2.4) to impart certain specific properties. These alloys are available as either castings or wrought products, such as extruded bars and shapes, forgings, and rolled plates and sheets.

Table 2.4: Properties and typical forms of various wrought magnesium alloys Composition (wt%)

Type

σT S (MPa)

σy (MPa)

Ductility (%EL)

Typical Forms

F H24

260 290

200 220

15 15

Extrusions Sheets and plates Extrusions and forgings Sheets and plates Extrusions and forgings

Alloy AZ31B

Al 3

Zn 1

Mn 0.2

AZ80A

8.5

0.5

0.2

380

0.7

H24

255

365

HK31A* ZK60A

5.7

0.55

* HK31A also contains 3 wt% Th

Applications: aircraft and missile components, material-handling equipment, portable power tools (such as drills and sanders), luggage, bicycles, sporting goods, printing and textile machinery, and general lightweight components. Miscellaneous: Because magnesium alloys oxidize rapidly, they are a potential hazard, and precautions must be taken when machining, grinding, or sand casting magnesium alloys. However, products made of magnesium and its alloys are not a fire hazard.

2.6.2

Sustainability

New magnesium-base scrap typically is categorized into one of six types. • Type 1 is high-grade clean scrap, generally such material as drippings, gates, and runners from die-casting operations that is uncontaminated with oils. • Type 2 is clean scrap that contains steel or aluminum, but no brass or copper. • Type 3 is painted scrap castings that may contain steel or aluminum, but no brass or copper. • Type 4 is unclean metal scrap that is oily or contaminated. • Type 5 is chips, machinings that may be oily or wet, or swarf. • Type 6 is residues (crucible sludge, dross, etc.) that are free of silica sand. 25

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CHAPTER 2. METAL ALLOYS The most desirable type of scrap is type 1. Most of the type 1 scrap is generated during die-casting magnesium alloys; this typically represents 40 % to 60 % of the total cast weight, most of which consists of runners that feed the die cavity as it is injected with magnesium. This scrap is either reprocessed at the die-casting facility or sold to a scrap processor. The other types of scrap are either sold to a scrap processor or are used directly in steel desulfurization. In addition to magnesium-base scrap, significant quantities of magnesium are contained in aluminum alloys that also can be recycled. In 2002, over 45 % of the supplied magnesium in the United States was generated from recycling [26] .

Copper Alloys 2.7.1

Material Properties

First produced in about 4000 B.C., copper and its alloys have properties somewhat similar to those of aluminum alloys. • Properties: high electrical and thermal conductivity; good resistance to corrosion and wear; easily processed by various forming, machining, casting, and joining techniques; high recyclability • Available Forms: Brass, which is an alloy of copper and zinc, was one of the earliest alloys developed and has numerous applications (see Table 2.5). Bronze is an alloy of copper and tin (see Table 2.6). Other bronzes include: – – – –

aluminum bronze, an alloy of copper and aluminum, tin bronze, beryllium bronze (a beryllium copper), and phosphor bronze; the latter two have good strength and high hardness for applications such as springs and bearings.

• Applications: electrical and electronic components, springs, cartridges for small arms, plumbing, heat exchangers, and marine hardware, as well as some consumer goods, such as cooking utensils, jewelry, and other decorative objects.

2.7.2

Sustainability

Copper’s recycling value is so high that premium-grade scrap holds at least 95 % of the value of the primary metal from newly mined ore. Recycling copper saves up to 85 % of the energy used in primary production. In order to extract copper from copper ore, the energy required is approximately 108 J/kg. Recycling copper uses much less energy, about 1.06 × 107 J/kg. By using copper scrap, we reduce CO2 emissions by 65 %. Almost 40 % of the world’s demand for copper is met using recycled material [28] .

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CHAPTER 2. METAL ALLOYS

Table 2.5: Properties and typical applications of various wrought copper and brasses [27] Type (UNS)

Oxygenfree electronic (C10100)

Nominal Composition (wt%) 99.99 Cu

Tensile Yield Strength Strength (MPa) (MPa)

Ductility (%EL)

Typical Applications

Bus bars, waveguides, hollow conductors, lead in wires, coaxial cables and tubes, microwave tubes, rectifiers. Weather stripping, conduit, sockets, fasteners, fire extinguishers, condenser and heat-exchanger tubing. Battery caps, bellows, musical instruments, clock dials, flexible hose. Gears, pinions, automatic high-speed screw-machine parts

220-450

70-365

55-4

Red Brass (C23000)

85.0 Cu, 15.0 Zn

270-272

70-435

55-3

Low Brass (C24000)

80.0 Cu, 20.0 Zn

300-850

80-450

55-3

Freecutting brass (C36000) Naval Brass (C46400 to C46700)

61.5 Cu, 3.0 Pb, 35.5 Zn

340-470

125-310

53-18

60.0 Cu, 39.25 Zn, 0.75 Sn

380-610

170-455

50-17

Aircraft turnbuckle barrels, balls, bolts, marine hardware, valve stems, condenser plates.

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CHAPTER 2. METAL ALLOYS

Table 2.6: Properties and typical applications of various wrought bronzes [27] Type (UNS)

Architectural Bronze (C38500) Phosphor bronze, 5 %A (C51500) Freecutting phosphor bronze (C54400) Lowsilicon bronze, B (C65100) Nickelsilver, 65-18 (C74500)

Nominal Composition (wt%) 57.0 Cu, 3.0 Pb, 40.0 Zn

Tensile Strength (MPa)

Yield Strength (MPa)

Ductility (%EL)

Typical Applications

415

140 (as extruded)

Architectural extrusions, storefronts, thresholds, trim, butts, hinges.

95.0 Cu, 5.0 Sn, trace P

325-960

130-550

64-2

88.0 Cu, 4.0 Pb, 4.0 Zn, 4.0 Sn

300-520

130-435

50-15

Bellows, clutch disks, cotter pins, diaphragms, fasteners, wire brushes, chemical hardware, textile machinery. Bearings, bushings, gears, pinions, shafts, thrust washers, valve parts.

98.5 Cu, 1.5 Si

275-655

100-475

55-11

65.0 Cu, 17.0 Zn, 18.0 Ni

390-710

170-620

45-3

Hydraulic pressure lines, bolts, marine hardware, electrical conduits, heat-exchanger tubing. Rivets, screws, zippers, camera parts, base for silver plate, nameplates, etching stock

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CHAPTER 2. METAL ALLOYS

Nickel 2.8.1

Material Properties

Nickel is a major alloying element that imparts strength, toughness, and corrosion resistance to metals. • Properties: high strength and toughness (at elevated temperatures for nickel-based alloys), good resistance to corrosion and wear, magnetic • Available Forms: A variety of nickel alloys that have a range of strengths at different temperatures are shown in Table 2.7. Monel is a nickel-copper alloy, and Inconel is a nickel-chromium alloy. Hastelloy, a nick-molybdenum-chromium alloy, has good corrosion resistance and high strength at elevated temperatures. Nichrome, an alloy of nickel, chromium, and iron, has high oxidation and electrical resistance and is commonly used for electrical-heating elements. Invar, an alloy of iron and nickel, has a low coefficient of thermal expansion and has been used in precision scientific instruments and camera/optics applications. • Applications: – Nickel-base alloys are used for high-temperature applications, such as jet-engine components, rockets, and nuclear power plants, as well as in food-handling and chemical processing equipment, coins, and marine applications. – Because nickel is magnetic, its alloys are also used in electromagnetic applications such as solenoids. – The principal use of nickel is in electroplating for resistance to corrosion and wear and for appearance. – Nickel (III) oxide is used as the cathode in many rechargeable batteries, including nickel-cadmium, nickel-iron, nickel hydrogen, and nickel-metal hydride, and used by certain manufacturers in Li-ion batteries.

2.8.2

Sustainability

Austenitic stainless steel scrap is the largest source of secondary nickel for the United States, accounting for about 86 % of nickel reclaimed in 2002. An additional 4 % came from the recycling of alloy steel scrap. The remaining 10 % comprised copper-nickel and aluminumnickel alloy scrap and pure nickel scrap. Scrap availability is expected to grow along with stainless steel production [26] . In addition, 80 % of nickel produced today comes from recycled material [29] .

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CHAPTER 2. METAL ALLOYS

Table 2.7: Properties and typical applications of various nickel alloys (all alloy names are trade names) Alloy (Condition)

Nominal Comp. (wt%) None

ﾏサ S (MPA)

ﾏズ (MPa)

Ductility (wt%)

Typical Applications

380 to 550

100 to 275

60-40

Duranickel 301 (age hardened) Monel R-405 (hot rolled) Monel K-500 (age hardened) Inconel 600 (annealed)

4.4 Al, 0.6 Ti

1300

900

30 Cu

525

230

Chemical- and food-processing industry, aerospace equipment, electronic parts. Springs, plastic-extrusion equipment, molds for glass. Screw-machine products, water-meter parts.

29 Cu, 3 Al

1050

750

Pump shafts, valve stems, springs.

15 Cr, 8.0 Fe

640

210

Hastelloy C-4 (solution treated and quenched)

16 Cr, 15 Mo

785

400

Gas-turbine parts, heat-treating equipment, electronic parts, nuclear reactors. High-temperature stability, resistance to stress-corrosion cracking.

Nickel 200 (annealed)

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CHAPTER 2. METAL ALLOYS

Zinc 2.9.1

Material Properties

Zinc, which has a bluish-white color, is the fourth most industrially utilized metal, after iron, aluminum, and copper. • Properties: high resistance to corrosion and wear; good formability characteristics; high recyclability • Applications: – For galvanizing iron, steel sheet, and wire, Zinc serves as the anode and protects the steel (cathode) from corrosive attack should the coating be scratched or punctured. – Zinc-base alloys are used extensively in die casting for making products such as fuel pumps and grills for automobiles, components for household appliances (such as vacuum cleaners, washing machines, and kitchen equipment), machine parts, and photoengraving plates. Major alloying elements in zinc are aluminum, copper, and magnesium. They impart strength and provide dimensional control during casting of the metal. – Zinc is also used as an alloying element; brass, for example, is an alloy of copper and zinc. – Another use for zinc is in superplastic alloys, which have good formability characteristics by virtue of their capacity to undergo large deformation without failure.

2.9.2

Sustainability

The average car contains up to 10 kg of zinc in its galvanized body panels. When they are discarded, these panels can be readily made into new parts of comparable quality. Total recovery of zinc within the non-ferrous metals industry amounts to 2.9 million tons, of which 1.5 million are new scrap or process residues and 1.4 million are old scrap. Secondary zinc production uses 76 % less energy than primary. Nearly 70 % of zinc from end-of-life products is recycled. Old zinc scrap consists primarily of die cast parts, brass objects, end-oflife vehicles, household appliances, old air conditioning ducts, obsolete highway barriers, and street lighting. Over 30 % of the world’s demand for zinc is met using recycled material [28] .

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Chapter 3 Plastics Ever since the development of plastics in the middle of the 20th century, the use of the material has exploded and found new applications in a wide variety of fields. Plastic’s appeal lies in its durability, its ease of manipulation, its versatility, and its relatively low cost. Designing with plastics has become the status quo, and it is important to understand this remarkable material so that the design can be as efficient and sustainable as possible.

Material Properties With their many uses and low cost, plastics have made many of our current products and conveniences possible. Plastics have become such a popular material in today’s society for one main reason: the range of properties and designs. [30]

3.1.1

Molecular Properties of Plastics

Most plastics (also known as “resins”) are organic high polymers. This means that they are carbon-based molecules with large chain-like structures. The large chain-like structures are formed by piecing together several monomers (a short-chain molecule) in a reaction process known as polymerization. Carbon-based raw materials are needed to make plastics. These raw materials can come from natural sources such as animal remains, plants, and insects. However, most materials used to make plastic are synthetic, or man-made. Some synthetic plastics come from natural gas, but are mostly made from crude oil. In order to make plastic from crude oil, the oil is refined and gases are given off. These gases are then broken down into monomers. These monomers are used in the polymerization process to make the plastic. [31]

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CHAPTER 3. PLASTICS

3.1.2

Types of Plastics

There are two main types of plastics: thermoplastics and thermosetting plastics. Thermoplastics consist of several lines of molecules that do not have many cross-linked; they are not tangled together. Because of this, thermoplastics become soft and malleable when heated and can be formed to whatever shape is needed. The thermoplastic will become stiff again when cold. Also, thermoplastics can be heated, reformed, and cooled several times. Some examples of thermoplastics include polyvinylchloride (PVC), nylon, acrylic, polycarbonate, and Acrylonitrile Butadiene Styrene (ABS). • PVC is a plastic that can be either flexible or rigid and is chemically nonreactive. It can be used in many applications. • Nylon is a moderate to high-priced plastic with excellent chemical and wear resistance, and is used in applications such as electrical connectors, fishing lines, and brush bristles. • Acrylic is a plastic that has half the density of glass, is impact resistant, is unaffected by sunlight, and can be used in a wide range of temperatures. • Polycarbonate is a strong transparent plastic that maintains its properties over a wide range of temperatures. It is used for lenses, windows, and automotive parts. • ABS is an inexpensive material with high impact strength, and is ideal for machine parts and tote bins. Thermosetting plastics consist of several lines of molecules that have many cross-linkages; they are tangled together. Because of the many cross-links, thermosetting plastics have a very rigid molecular structure. Unlike thermoplastics, thermosetting plastics can only be shaped once; after the initial heating and shaping, the plastic will be permanently stiff. Thermosetting plastics are a dense yet lightweight material with great heat and chemical resistance. They are best used for gears, switches, and gaskets. Examples of thermosets include phenolics, epoxies, and melamines. • Phenolics are a type of plastic that is simple to mold, and are also strong, brittle, and hard. They are often used for potting compounds, casting resins, and laminating resins. • Epoxies are relatively easy to cure, are very elastic, and have exceptional chemical resistance. They are also very strong, and can be found in aircraft engines, tanks, pressure vessels, and industrial equipment. • Melamine is a plastic that is very easy to color and is very hard. It is often used in household goods such as dinnerware. [31;32;30;33]

3.1.3

Properties of Plastics to Consider

When choosing a plastic for a product, there are several plastic properties to be considered. One thing that is of note is that because of the many different types of plastics available, a wide range of possibilities is available for almost all properties. 35

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CHAPTER 3. PLASTICS 1. Cost: Plastics have a wide range of costs, with raw materials costing as little as $0.90 per pound or as much a $50 per pound for specialty plastics. In terms of sustainability impact, cheaper plastics are produced in much larger amounts than specialty plastics, and thus it is very important to determine a sustainable way of disposing of cheap plastics. It is also important to determine a way for cheap plastics to last as long as possible before being disposed. Some cheaper plastics are PVC, polystyrene, and ABS, while nylons tend to be moderately to highly expensive. Also, thermosetting plastics tend to be more expensive than thermoplastics due to their more complex creation process. 2. Hardness: Plastics have a wide range in this property as well, ranging from as soft as a rubber eraser, to as hard as some metals. Epoxies and melamines tend to be very hard. 3. Flexural Strength: Some plastics, especially rubbers, will not break. However, there are some more brittle plastics available, such as phenolic plastics, which will break with just a slight bend. This impacts sustainability in that flexural strength has an effect in a productâ&#x20AC;&#x2122;s life cycle. 4. Stiffness: For many uses of plastics, it is important for it to have resistance to flexing. Some examples of plastic applications where stiffness is important are snap-fit parts and springs. Polystyrene tends to be rather flexible, but polybutylene (a plastic used in piping) and polyphenylene sulfide (a plastic used in auto parts) tend to be very stiff. 5. Tensile Strength: It is often important that the plastic hold its shape under large and/or sustained loads. An example of where tensile strength is an important property is plastic handles. This is much less of an issue for rubber erasers. Epoxies and melamines have high tensile strength, and polystrene is much weaker to tension. 6. Creep: All materials, including plastics, have shape distortions under pressure. For some applications of plastics, such as plastic fasteners, it is very important that there be no permanent deformations from constantly applied pressures. An example of a plastic that is resistant to creep is polybutylene, which is used in piping and film. Creep is important in terms of sustainability because creep resistant plastics last longer, leading to a longer product life cycle, and less replacement and disposal. 7. Temperature Resistance: Extreme temperatures can affect the shape of a plastic, so this is an important consideration. Plastics exposed to large amounts of heat, such as plastics in coffee brewers and hair dryers, require high temperature resistance. Plastics exposed to freezing temperatures, such as plastics used inside of freezers, should be flexible to withstand contractions due to the low temperature. Most thermosetting plastics have strong resistances to temperature, as do polycarbonates, polyphenylene sulfide, and fluoropolymers. 8. Elongation: For many plastics, it is important to know how much the material can stretch before it begins to neck and ultimately break. This is especially important for rubbers, which must be able to stretch rather extensively before breaking. Polyurethane often has good elongation properties. 9. Acceptance: Plastics that are designed to be in contact with food, drink, and drugs, as well as surgical plastics, must be safe biologically and satisfy FDA regulations. Polystyrene is an example of a plastic used widely in many consumer applications.

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CHAPTER 3. PLASTICS 10. Chemical Resistance: Plastics have a wide range of chemical resistance, with plastics such as polyethylene and nylon remaining inert with a wide array of substances, and other plastics breaking down easily when exposed to certain chemicals. These characteristics can be very useful. For example, many disposable products are made of styrene, which breaks down easily in the presence of sunlight and bacteria. Also, plumbing fittings and medical implants, which require a long life, use plastics that are much harder to break down. 11. Color: Most plastics are colored easily, but some are harder to color properly, especially if the plastic has fillers or modifiers. Color is important for highly visible parts for customer products, but is not so important with internal parts such as gears. Melamine, a plastic often used for dishware, is very easy to color. The inks used to color the plastic may affect its recyclability (see the Recyclability section in this chapter). 12. Clarity: Some plastics are completely opaque, but they also can be clear or clear-tinted. Some types of plastic, including acrylic, can be used as lenses. [34]

Production Plastics are shaped and formed into necessary parts using many different mechanical, thermal, and chemical processes. These processes will be explored and discussed in the following section.

3.2.1

Mechanical Creation of Plastic Products

Creation processes for forming plastic parts are very similar to metallic manufacturing processes, with a few key differences. One of the main differences between the two material types is that the melting temperatures of plastics are much lower than those of metals. This makes deformation and manufacturing of plastics much easier, requiring less energy and providing more options in the design of mold cavities and dies. Another thermal difference between the two materials is that plastics, in general, have a much higher coefficient of volumetric thermal expansion. This has to be taken into account when molding plastic parts, because when the plastic cools, it will shrink in volume, causing part deformation. Extrusion: Extrusion is a form of plastic part manufacturing in which plastic pellets are fed into a hopper and pushed through a long heated chamber which is moved by hydraulic, screw, or other continuous even force. Pellets are melted by the heat of the extruder, and are then forced through a die or small opening. The plastic is then cooled by air or water for the final product. Extrusion is often used for long, constant cross section pieces. [35] Injection Molding: In a similar manner to extrusion, injection molding is when pellets or granules are heated into a liquid state, then pushed, sometimes using very high pressures, into a mold cavity. The plastic then cools in the mold and the mold is removed, and the 37

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CHAPTER 3. PLASTICS

Figure 3.1: Extrusion [36]

final product is finished. Injection molding is often used to make products such as closures, fittings, and solid, homogenous plastic pieces. [35] Blow Molding: Blow molding is often used in conjunction with extrusion or injection molding. One form of blow molding is when a semi-molten tube of thermoplastic material is clamped and air is blown through the interior to conform the tube to the interior of the mold and to cool and solidify the stretched tube. Overall, it is used to manufacture hollow plastic products, and allows better control of the interior of a plastic material. It can be used to create objects such as commercial drums, milk bottles, and other hollow containers. [35] Rotational Molding: Rotational molding is when centrifugal forces are used to form a plastic into the inside of a mold cavity by high speed rotation. Rotational molding is similar to blow molding in that it is a process that controls the formation of the interior of a plastic part. [35]

3.2.2

Chemical Creation of Plastics

Before plastics can be mechanically molded into useful shapes, they must be chemically created by combining other materials. This process gives the each different plastic its different characteristics, based on its chemical composition. In most cases, plastics are chemically composed of monomers combining to form repeating, semi infinite chains. Chemically, the majority of plastics are made by treating oil and natural gas in a â&#x20AC;&#x153;cracking process,â&#x20AC;? converting to these monomers. During creation processes, most plastics are combined with additives to improve mechanical properties, provide color or flame retardancy, or fight degrading effects of light, heat or bacteria. [35]

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Figure 3.2: Injection molding [37]

Figure 3.3: Blow molding [38]

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Figure 3.4: Rotational molding [39]

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3.2.3

Creation of Bioplastics

Bioplastics are a form of plastics created using renewable biomass sources such as corn starch, potato starch, vegetable fats, and microbiota instead of oil or natural gas. It has been used in food packaging, the automotive industry, multiple medical devices, computer hardware, and toys. However, many bioplastics do not have comparable material properties to normal plastics. To remedy this, bioplastics are combined with silica-based plastics, which have led to an increased flame resistance, among improvement of other properties, without using halogens or phosphorus. [40]

Lifetime The life of a plastic part greatly depends on the part’s function. There are, however, certain conditions that affect the life of a plastic part that can be separated into material factors, environmental factors, and loading factors. Material factors are those that were discussed in Section 1 of this Chapter. Examples of environmental factors include: • • • • • •

Chemical exposure Temperature Pressure Moisture Radiation Sunlight exposure

Since the properties and behaviors of plastics are susceptible to change under these influences, it is important to select a material that is durable for the particular setting. This can be done experimentally by mimicking real-life conditions to reach conclusions about how plastics will hold up over time in certain environments. For example, chemical resistance tests can be carried out on the material to examine how the composition of the plastic material and its structure change. Figure 3.5 is a diagram showing how chemicals can damage plastics, lowering their life and leading to failure. Loading factors attribute to the wear of plastic parts. When examining the loading on plastic it is important to ask the following questions: • • • •

What load will the part have to carry? Will the part be subjected to impact? Will the part endure cyclic loading? What environmental factors will the part be subjected to?

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CHAPTER 3. PLASTICS

Figure 3.5: Effects of chemicals on plastic wear

The plastic’s ability to cope with these loading aspects is heavily dependent on its material properties. For example, certain plastics are better chemically-formulated for rubbing against certain surfaces, as some exhibit self-lubricating properties. [41] Testing the plastic in similar environmental and loading conditions to those in which it will perform will make it possible to examine the part’s lifetime and choose the correct material.

3.3.1

Economics of Processing Plastics

The processing costs of different plastics is ultimately dependent on the costs of equipment, tooling, and production. These factors are all affected by the volume of production. The larger the production run, the more expensive the machinery can be for processing and tooling. Due to plastic’s wide range of possible processing techniques, there are many options to choose the most economical method of production based on equipment cost, production rate, tooling cost, and production volume. The most expensive plastic forming and shaping process is injection-molding, where the cost is directly proportional to the clamping force used in the process. A typical machine with a 2,000 kN clamping force costs approximately $110,000 while a clamping force of 20,000 kN costs roughly $450,000. Costs increase with composite materials, as equipment and tooling expenses increase. [42] Size of the part also strongly affects the cost of processing. For example, in die casting, the larger the part, the larger the die must be. This increases the tooling cost. Though this results in a more expensive process, a larger die is able to produce more parts, increasing the total production rate.

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CHAPTER 3. PLASTICS

Figure 3.6: Cost comparison of material processing

Figure 3.6 shows how through careful material selection and design, the cost of plastic processing (Nylon 66 shown here) can be lower than other materials’ processing costs since there is no need to perform finishing operations that another material might require. It compares the cost of a material broken down into production costs, ranging from material and energy to production and finishing costs. The following measures should be taken to avoid the cost of processing plastics: • The design of a plastic is imperative when it comes to cost reduction, as the production cost is predetermined in the part’s design. Optimization at a later stage is costly and impracticable. To reduce cost, the design should combine multiple functions within one part by incorporating multiple integrated functions within a single machined part, reducing the total number of parts needed, and thus simplifying assembly. For example, a driving rod and gear can be molded together, eliminating the need for post-production fastening. • Low cost assembly techniques should be used to simplify the assembly process through snap-fits, welds, and rivets. This will make assembly easier so fewer resources will have to be used. • The design should use dry running properties, since this will eliminate the need for additional lubrication. For example, delrin acetal resins can be used since they have low wear when interacting with metals. [43]

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Recycling When designing products to be recycled it is important that the designers understand if the plastic used in the product is recyclable and the process in which it will be recycled as introduced by the Association of Postconsumer Plastic Recyclers (APR). The major recycling systems have specific requirements that need to be met in order to recycle specific plastics. If these requirements are not met, not only does it make the product un-recyclable, but if it gets into the system it could possibly contaminate a large number of recyclable plastics. It is important to note that the types of plastics, labels, inks, and connections are all factors affecting the productâ&#x20AC;&#x2122;s recyclability. Making sure that the entire product is ready for recycling will ensure a high efficiency recycling rate for products and would save material cost for the consumer, the seller, and the recycler. [44] . When developing a product, it is important to know the processes that created the plastics you will use. Thermoplastics and thermosets [45] . Examples of thermoplastics are high density polyethylene (HDPE), low density polyethylene (LDPE), polyethylene terephthalate (PET), and polyvinyl chloride (PVC). In general, thermoplastics are easily recycled; an exception is when compositions of thermoplastics are created [45] . This makes it difficult to separate the thermoplastics and therefore undesirable for recycling. Thermosets are very difficult to recycle; products that seek to have high yield recycle rates should seek to minimize the use of such materials. Table 3.1 displays a list of common thermoplastics and their densities. In order to efficiently separate the plastics in a composition, the densities should differ by 1 gram per cubic centimeter.

Table 3.1: Densities of common plastics [44] Material PP LDPE HDPE PET PLA PVC PS

Density (g/cm3 ) 0.90 to 0.92 0.91 to 0.93 0.94 to 0.96 1.35 to 1.38 1.24 to 1.27 1.32 to 1.42 1.03 to 1.06

The first process in recycling a product is the manual separation of the different plastics and all materials that if mixed together could possibly contaminate a batch of recycled material. Separating these parts is a labor intensive process that could still allow unwanted pieces to be mixed in the plastic that is to be recycled. Traditional sink/float recycling processes require that plastics with overlapping densities be recycled separately. Plastics that have overlapping density ranges require a more advanced separating system and will increase the cost of recycling the product. The next step in the process is the automatic separation with the sink/float process. In this process, the plastics are ground into small 44

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CHAPTER 3. PLASTICS pieces, separated by their different densities, and washed with detergents to remove labels and adhesives. If the label and adhesives do not separate from the plastics during this process then the batch is contaminated and cannot be efficiently recycled. The attachments and closures are important when the plastics are being separated; their densities should not overlap with the density of any other parts of the product. Examples for the proper adhesives, labels, and inks can be found on the Plastics Recycling Website. After the plastic has been separated, ground, washed, and dried, some of the contaminants may still remain in the plastic. Filtration takes place in an extruder and the end product is recycled plastic in the form of pellets that are ready to be remanufactured. When melted, the contaminants may not get filtered and can render a batch of recyclables useless.

Sustainability Plastics are becoming ever more prevalent in modern design. Compared with metal, they are less expensive and easier to obtain and transport. But are they more sustainable than other materials? And if so, what is it about plastics that makes them a sustainable choice for product design?

3.5.1

Sustainable Solutions

Plastics serve as a valuable resource for designers. One main reason for this is the resource efficiency that can be gained by using plastic products. For example, while over 50 % of product packaging is plastic, only 17 % of packaging weight is attributed to plastics [46] . The ability to do more with less is the main sustainable appeal of plastic; a little bit can go a long way. Another sustainable appeal about plastics is their versatility. The same type of plastic can be used in a number of different products, which can extend the life of recycled plastics to a number of different applications. For example, PVC from windows and pipes can be recycled into a number of different products, and polyolefins (which are used in industrial packaging) can be recycled and reused in products such as shopping bags, windshield wipers, and food and agricultural containers [46] . The final main sustainable feature of plastic is the ability to use it to conserve energy. Plastics are used in insulation material in several applications, and using plastic components instead of metal in vehicles such as automobiles or aircraft reduces weight and, subsequently, fuel usage and resulting emissions. If plastics cannot easily be recycled, they can sometimes be recovered and used as an energy source to generate heat or electricity. This practice is becoming increasingly popular in Europe. [46] Plastics have also revolutionized the capture of renewable energy by enabling and assisting with technological advancements such as wind turbines and solar panels [46] .

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3.5.2

Problems with Plastics

There are some properties of plastics that make them an unsustainable material for design choices. First of all, many plastics are made using fossil fuels, especially petroleum. Fossil fuels are not only unsustainable by their limited quantity but also by the methods which are used to mine them. These plastics are also manufactured using carcinogens and other toxins that are harmful to both humans and the environment. [47] These toxins are released into the environment when the plastics are incinerated or decomposed in a landfill; they can then reach human populations through a toxin spread in the soil. An increased interest in bioplastics, which use renewable resources instead of fossil fuels as bases, has been a result in the effort to make plastic production more sustainable. However, even the use of renewable resources can be problematic. As the market for biological sources continues to grow, biodiversity is threatened by the continuous removal of these resources from their natural environments and by the expansion of agricultural initiatives that focus exclusively on cultivating these materials.

3.5.3

The Plastic Scorecard

With so many different types of plastics used in consumer products, it can be difficult to determine which types are more sustainable than others. When sustainability plays a key role in the material choice of a design, it is important to be able to rank the plastics to determine the most suitable choice for the product. One way to do this is by using the Plastic Scorecard. [47]

Figure 3.7: Plastic scorecard example [47] The Plastic Scorecard (shown in Figure 3.7) is a policy which ranks the sustainability of different plastics by three principles: Sustainable Resources, Green Chemistry, and Closed Loop Material Flows. The principle of Sustainable Resources seeks new biological sources for plastic production that are less harmful and intrusive to the environment than fossil fuels, and also explores ways in which these materials can be gathered successfully. Green 46

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CHAPTER 3. PLASTICS Chemistry is the process of limiting and reducing the toxins in plastics so that their disposal is less destructive to the environment. Finally, the Closed Loop Material Flows principle emphasizes the importance of using plastics that can easily be recycled and remade into the same product, thereby recirculating plastics through the market rather than producing new plastics to replace products that have been thrown away. When evaluated by the beta version of the Plastic Scorecard, the most harmful type of plastic was polyvinyl chloride (PVC), with polylactic acid (PLA) and polypropylene (PP) type plastics earning a higher sustainability score. Conclusion The use of plastics in design has become almost universal, and it is increasingly difficult to find a product that does not employ the material in its design. As technological advancements in material science continue to be made, the use of plastics is becoming increasingly sustainable. Knowing which types of plastic to use and the ways in which they can be recycled after consumption can also increase sustainability on the level of design.

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Chapter 4 Ceramics, Composites and Elastomers The material selection guidelines for metals and plastics are established in Chapter 2 and Chapter 3. There are additional categories of materials, commonly used in engineering applications, that also require guidance for selection. These materials fall under the classifications of ceramics, composites and elastomers. While these types are used less frequently, they still have important and unique characteristics, and should be considered in the design process. This chapter will discuss the properties of each category, as well as provide some input as to the sustainable qualities of each.

Ceramics Ceramics materials are created from combinations of fine particles of metallic and non-metallic elements, resulting in a wide variety of ceramics available for different engineering applications. They are used in the aerospace, automotive, computer, medical and household product industries. Generally, ceramics are characterized as brittle materials with high strength, melting temperature, surface hardness, and electrical resistance.

4.1.1

Material Properties

Since ceramics are created by combining elements, the properties vary greatly. This also means that a ceramic can be designed to have certain characteristics by controlling the additives. Oxide ceramics are great electrical and thermal insulators. Carbide ceramics have a rough surface finish, making them useful for abrasive parts such as grinding wheels. Nitrides are extremely strong and can make cutting tools [48] . Table 4.1 contains a few common ceramics and their physical characteristics. As demonstrated by this table, the compressive strength of ceramics is significantly larger than the tensile strength. Ceramics fail more easily 50

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CHAPTER 4. CERAMICS, COMPOSITES AND ELASTOMERS under tensile strain due to the impurities in the material structure. These impurities cause ceramics to be susceptible to surface cracking, and allow fast crack propagation throughout the material.

Table 4.1: Material properties of ceramics [49] Compressive

Elastic

Hardness

Strength (MPa)

Modulus (GPa)

(HK)

Aluminum oxide

1000-2900

310-410

2000-3000

Density kg m3 4000-4500

Cubic boron nitride

7000

850

4000-5000

3480

Diamond

7000

830-1000

7000-8000

3500

Silica, fused

1300

550

–

Silicon carbide

700-3500

240-480

2100-3000

3100

Silicon nitride

–

300-310

2000-2500

3300

Titanium carbide

3100-3850

310-410

1800-3200

5500-5800

Tungsten carbide

4100-5900

520-700

1800-2400

10,000-15,000

Zirconia

–

200

1100

5800

Material

Due to the brittle nature of ceramics, their lifetime is heavily dependent on surface defects, material impurities and incidental cracks. An experiment at RWTH Aachen University in Germany tested various alumina and zirconia ceramics to find a material with a suitable lifetime for dental crowns and bridges. The results of the experiment can be seen in Figure 4.1. This figure proves that the lifetime of ceramics depends heavily on the material composition and environment in which it is used. Since the lifetime of ceramic material can vary so drastically, ceramics need to be heavily researched prior to use in order to find a type that will fulfill the desired application. Additionally, the cost of ceramic material should be considered. Purchasing raw ceramic material is inexpensive (around $0.50 per lb) [51] . The largest expenses in ceramic production are the manufacturing and tooling costs, as described in Section 9.2.

4.1.2

Material Production and Recycling

Ceramics can be created from a variety of materials in several different processes. Each creation procedure involves the same basic steps of grinding raw material into fine particles, adding new materials to the crushed particles to create the desired characteristics, shaping the mixed material, then drying or firing the finished work piece [48] . There are three main processes for shaping ceramics: 1. Pressing: A large hydraulic compactor is used to press the material into a die of the desired shape. 51

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Figure 4.1: RWTH ceramics lifetime testing [50] 2. Plastic forming: The material is shaped by plastic deformation through extrusions, jiggering, and injection molds. 3. Casting: Liquid (melted) material is formed by solidifying (cooling) in a mold of the desired shape. In general, manufacturing ceramic material is more expensive than manufacturing plastics or metals due to the strength and resistance of ceramics. Tool surfaces are scratched and worn out after a few ceramic forming processes, so they need to be replaced often or made from heavily resilient material. Ceramics are created throughout the world. To locate or order ceramics, visit the webpage of the International Ceramics Directory. This website is a directory of ceramic companies, featuring information for obtaining ceramic material or ordering the equipment to produce ceramics for various engineering applications. Despite ceramicsâ&#x20AC;&#x2122; brittleness and weak shearing thresholds, the recyclability of the material is very low compared to most other manufacturing materials. This is mainly due to the crystalline structure of the material, which leads to very strong molecular bonds. With the exception of glass and brick, ceramics are very difficult to reshape. Certain ceramic products can be crushed into a powder and then extruded through a die into the new desired shape. In most cases, the energy and finances required to truly recycle ceramics is higher than simply developing new ones. Despite the many characteristics that make ceramics difficult to recycle, two widely used materials, brick and silicon subsidiary compounds, are still capable of being recycled with 52

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Figure 4.2: Recycling versus cost for various materials [52] relative ease. Bricks that are turned in to recycling programs are often evaluated on a set of manufacturing standards to see if they can be reused without any additional treatments [53] . Those that do not pass the set of manufacturer’s criteria are typically crushed down to brick chips that are either used as a landscaping medium, or as a powder to create new bricks. Because of silicon’s high electronegativity and metalloid characteristics, it is typically combined with other materials to develop compounds particularly suited to a need such as silica sand, clay, cement, concrete, and even bricks. Because of the vast number of possible applications for silicon, there also exists a great deal of potential recycling techniques. Used silicon can be extracted and purified for use in technological applications such as solar panels and silicon wafers. Materials such as concrete, mortar, and cement can be crushed down to various sizes for use as road layers, riprap (erosion control material), landscaping, and retaining walls. In certain applications, manufacturer standards need to be met before reuse, which may limit the amount of material that is considered recyclable.

4.1.3

Sustainability

When considering ceramics as a manufacturing material or design tool, it is important to consider its sustainability. Ceramics’ physical properties contribute to it being a long-lasting, durable material, allowing it to last for many years once installed or applied. These characteristics include: • lower susceptibility to wear, 53

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CHAPTER 4. CERAMICS, COMPOSITES AND ELASTOMERS • • • •

high hardness (relative to most metals), very low strains under load, high Young’s Modulus, and high resistance to heat, water, electricity, and most chemicals [54] .

Many of these traits can be desirable when developing a product that requires durability under high levels of stress and external forces. Despite the relatively low reusability of ceramics, as shown in Figure 4.2, the high durability of the materials give them much longer expected lives, leading to an overall balance in sustainability. If the product does not need to be replaced as often, less material and energy needs to be spent on reusing it. As with all materials, the characteristics of the application must be considered. When durable, high yield strength, and highly insulating materials are needed, ceramics typically provide a longer lasting, and more sustainable solution. Many insights into the benefits of using ceramics can be gained by examining the use of ceramics for vehicle disk brakes in consumer automobiles. As the brake is applied, the rotation of the tires is subjected to a frictional force which is then converted to energy in the form of heat. The insulating nature of ceramics allows the disc brakes to remain thermally resistant to the heat generated by the process. This can be extremely beneficial, since most materials are subject to point defects from heat, which can propagate into cracks and lead to failure. The cyclical nature of the forces on these brakes typically leads to the likelihood of failure, and because of ceramics’ physical characteristics, they are able to withstand the high levels of stress. As proven in this application, ceramics can outperform alternative materials, especially when cost is considered, leading to a sustainable and favorable end product.

Composites Composites are engineering materials that are made from two or more chemically distinct constituent materials. Composites are used because they allow engineers to tailor the properties of the material to the need of the application. Composite materials are made by embedding a reinforcing material into a matrix material. The composite material generally combines the strength of the reinforcing material with the toughness of the matrix material.

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Figure 4.3: Hybrid composite material [56] 4.2.1

Material Properties

There are many different composite materials that are used in as many different applications. Most composite materials have anisotropic material properties, varying with the direction of the applied load. The most common composite material is concrete. Concrete is used in a wide variety of applications because of its high compressive strength of 20 MPa to 40 MPa [55] , however, concrete has a very poor tensile strength of 2 MPa to 5 MPa [55] . Another very common composite is fiberglass. Fiberglass is strong in both tension and compression, lightweight, and very durable. Almost all composites can be classified under two categories: fiber-reinforced polymers and metal matrix composites. Fiber-reinforced polymers (or FRPâ&#x20AC;&#x2122;s) use reinforcing fibers to enhance the strength and elasticity of the polymer when the fibers are parallel to the applied load. This allows the material to be designed for a specific application in which the loading magnitude and direction are known. Metal matrix composites (or MMCâ&#x20AC;&#x2122;s) use a lightweight metal such as aluminum or magnesium as the matrix component. Metal matrix composites differ from polymer composites in that they can operate in a wider temperature range, have better thermal and electrical conductivity, and do not absorb moisture. Figure 4.3 is a diagram of a hybrid composite material. There is a honeycomb matrix of aluminum surrounded on the top and bottom by a layer of carbon fiber in a matrix of epoxy resin. Composite materials are among the most expensive materials used in engineering applications. This is due to the time and effort that is required for the production of these materials. The lifetime of composite materials depends heavily on the loading to which the material is subjected, however, composite materials are generally very durable. For example, fiber-reinforced composites are widely used on the exteriors of aerospace structures where fatigue life is of prime importance. This means that composite materials can be expected to have a long usable life. In the design process, the decision to use a composite material must be thoroughly considered. While they have a long life expectancy, composite materials should only be used when they are absolutely necessary because the production of composites requires much more energy than the production of other materials. 55

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4.2.2

Material Production and Recycling

There are many different methods used to create composite materials, but most methods follow the same general process. The constituent materials are combined in a melding process and then molded into the final shape. For polymer composites, the melding is a curing reaction that uses heat and/or chemical reactivity. For metal composites, the melding is performed at very high pressures and temperatures. There are a number of different methods used to mold the composite into its desired shape. Some of the most common molding methods include: • vacuum bag molding - the constituent materials are sealed in a bag made of polyurethane or vinyl, and air is pumped out of the bag to create uniform presssure over all surfaces, • pressure bag molding - the consituent materials are fused together under higher pressures than the vacuum bag molding process, and • autoclave molding - a two-sided mold is used in which one side is rigid and the other is made of flexible silicon or nylon. The mold assembly is placed in an autoclave at a high temperature and pressure. Out of the previously mentioned common composite materials, most are recyclable to some extent. Concrete is recycled through the use of crushing and sorting techniques [57] . The smaller pieces of concrete are used for aggregate base course (road base), ready mix concrete, soil stabilization, pipe bedding and landscape materials [58] . Fiberglass appears to be recyclable; however, there are no current fiberglass recycling facilities, nor does there appear to be any current uses of recycled fiberglass. Fiber-reinforced polymers can be recycled; however, the recycled material is generally not as strong as the original material. Despite this, recycled polymers have several uses in industrial applications and consumer electronics, such as laptops [59] . For more information on polymers, see Chapter 3. For metal matrix composites, recycling and reclamation have been very successful, especially with aluminum. Depending on the use of the MMC, some can be directly melted down and then reused as a composite material, such as in the case of cast MMC’s [60] .

4.2.3

Sustainability

The fact that composites generally have longer life spans makes these materials more sustainable in the long run. Aided by the recyclability of composite materials, there is also less overall material being utilized. Using composite materials can have other sustainable uses as well. For example, using 50 % composite materials on a Boeing 787 Deamliner will reduce the overall weight by 12 % [61] . The lower weight of the plane and the higher strength of the material allow the plane to use less fuel, therefore decreasing fossil fuel consumption and emissions.

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CHAPTER 4. CERAMICS, COMPOSITES AND ELASTOMERS There are many uses of composite materials seen all over the world today. As stated previously, the most common composite material is concrete. Composite materials are also widely used in the aerospace industry. They are used in the tail, wings, fuselage and propellers. Fiberglass is used in cars and boats as an alternative to steel and wood [61] . It is utilized in the bumpers and tire rims for cars and as the standard material used for all modern boats. It is also used for the blades for most wind turbines as an alternative to steel, making the turbines lighter and more durable. Composite materials can also be used for insulation when strands of fiber are interwoven with glass fibers. This insulation can be used anywhere such as home and building insulation, automobile engine parts, ship and submarine bulkheads, hulls, furnace, and air conditioning units [61] . Graphite epoxy, a carbon-reinforced polymer, is capable of withstanding extremely heavy loads and is used to reinforce bridge beams. This polymer reinforcement has shown to increase load capacity anywhere from 30 % to 65 % [61] . Composite materials are also valuable in military protection gear due to its varying elasticity and ability to withstand high temperatures and shock [61] . The uses of composites do not end here, however, as research is currently being done to find more applications of these materials.

Elastomers 4.3.1

Material Properties

Elastomers are another material that is used in engineering applications. This material is most commonly referred to as â&#x20AC;&#x153;rubber.â&#x20AC;? Natural rubber is the most widely used elastomer today. It has a tensile strength of about 27.6 MPa and an elongation of up to 700 %. Most elastomers have excellent tear and water resistance, but poor ozone and oil/gasoline resistance. An overview of the basic properties of elastomers can be found in Table 4.2.

Table 4.2: Basic properties of elastomers [62] Natural Rubber

Styrene Butadiene

Neoprene

Fluro Carbons

Silicone

0.93

1.23

1.4-1.9

0.95

Durometer Range

30-100

15-95

65-90

15-80

Tensile Strength, kPa

27500+

20700

13800+

9700+

Elongation, %

To 700

To 500

To 800

To 300

To 700

Tear Resistance

Excels

Good

Fair

Good

Weather Resistance

Fair

Excels

Ozone Resistance

Poor

Excels

Water Resistance

Excels

Good

Oil & Gasoline Resistance

Poor

Good

Excels

Poor

Solvent Resistance: Aliphatic

Poor

Good

Excels

Poor

Solvent Resistance: Aromatic

Poor

Excels

Poor

-60

-45

-50

-120

-40

-35

-20

-25

-100

Good

Fair

Good

Excels

Fair

Good

Excels

Temp Resistance to 177 C

Poor

Excels

Temp Resistance to 232 ◦ C

Poor

Excels

Gas Impermeability

Good

Fair

Good

Excels

Fair

Abrasion Resistance

Excels

Good

Fair

Flex Resistance

Excels

Good

Excels

Polymer Spec. Gravity

◦

Brittle Point C ◦

Stiffening Point C (avg) Compression Set Temp Resistance to 100 ◦ C ◦

CHAPTER 4. CERAMICS, COMPOSITES AND ELASTOMERS

Physical Properties

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CHAPTER 4. CERAMICS, COMPOSITES AND ELASTOMERS The lifetime of elastomers is dependent on the usage and size of the material in use. A model for estimating the lifetime of general models of elastomers can be found at Science Direct. The cost of rubber has increased greatly since 2009, jumping from a cost of $0.57 to $2.50 per pound in two years. This price increase is due to higher manufacturing demands and unfavorable conditions in countries that harvest natural rubber [64] .

4.3.2

Material Production and Recycling

There are four main types of creation processes for elastomers: 1. Compression: The material (rubber) is placed in a preform molding and pressed together to form the shape of the desired material. 2. Transfer molding: The material is forced through sprues into the mold cavity. 3. Injection molding: A screw inserts the rubber into the mold. 4. Liquid injection silicone molding: Two materials are mixed and then injected into a mold [65] . Elastomers are very difficult to recycle because most polymer chains are made of one molecule which is covalently bonded. New ways of breaking down these molecules are being investigated in order to find a way to create elastomers which are made up of chains of molecules whose links are easily broken. Until this new generation of rubber is created, recycling elastomers will remain difficult.

4.3.3

Sustainability

Although elastomers do not have a sustainable recycling process, companies such as CHEManager are researching ways in which elastomers can be used more efficiently. In the context of sustainability, rubber materials can be used to help improve the efficiency of a system. For example, elastomers are widely used as sealants in drainage pipes, as well as water supply equipment. The efficiency of solar panels is increased when they are covered by UV absorbant rubber. Elastomers serve an excellent purpose in improving the sustainability of systems, but are not sustainable when referring to their own recyclability. Some common applications of elastomers include gaskets, adhesives, and molded parts. One interesting example is the use of rubbers for boots. Recently, Dow has invented a renewable rubber sole that is created with less energy consumption because it contains natural oil polyols. This boot is called the Voralast R series because it is considered the Renewable line of their company [66] .

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Chapter 5 Machining and Tools The portion of design and manufacture which take place in the machine shop can be one of the most energy intensive. For the design portion, repeated prototyping attempts can add up, while the choice to use the high-powered tools for finall production can quickly add up to astronomical costs for an enterprize as well as the earth. From the designer’s standpoint, one of the biggest challenges is proper communication and careful forethought as to exactly how the processing of each project should be carried out. A disconnect can lead to high levels of inefficiency and wasteful practice. For the machinists themselves, extra care to follow some simple procedures can actually end up saving time as well as energy and material resources. In order to practice sustainable design and manufacturing, all material and energy uses must be carefully considered. Given this, the following will outline some ways in which designers of products and machining processes can properly approach some key issues.

Guidelines to Streamline Machining Processes “There are three basic types of waste produced by the manufacturing process. The first type, process wastes, are those that result from transforming lower-value feed materials into higher-value products. The second type, utility wastes, are those that result from the utility systems that are needed to power the manufacturing process. A third type results from start-ups and shutdowns, maintenance and other offhand operations.” – Reducing Manufacturing Waste, the Dupont Way. By Katrina C. Arabe [67] One of the main contributors to sustainability standards regarding any product is the time and energy necessary to manufacture the product in its entirety. Ultimately, the goal for any design or manufacturing engineer is to minimize time and error when the product is on the shop floor. This will help to reduce energy used, product waste and cost. It is better to spend more time in the upstream processes of design, implementation and procedure writing than to potentially waste machine time, energy and worst of all materials. Therefore 62

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CHAPTER 5. MACHINING AND TOOLS it is ideal that the engineer create a product manufacturing and assembly procedure that is thorough in its processes and verifications. The procedure should, at the least, consist of the following sections (suggested to be listed in this or a similar order): 1. Description of the specific product, its purpose and reference to any assembly it may be a part of. 2. Important safety notifications regarding manufacturing/assembly. 3. Necessary machinery and/or tools with appropriate safety equipment. 4. Detailed, step by step process outlining the manufacturing/assembly process. 5. Intermittent stops in work to check the quality and status of the product with operator sign-offs. 6. Requirement of quality verification from at least one other shop technician. 7. Storage and handling requirements (if necessary). It is important for the engineer to remember that the technician manufacturing or assembling the product knows only any information the engineer supplies to him. This being the case, the engineer and shop technician must dialogue often, expressing any thoughts and ideas regarding the process.

Designing for Maximum Reusable Material Within the realm of manufacturing there are multiple avenues through which to come closer to achieving a state of sustainability. This section will outline those processes which are considered the most sustainable and those which are less so, stressing the importance of the selection of both manufacturing processes and the manufacturing plant in the design of a product.

5.2.1

Input Energy and Pollutant Production

The first two factors to consider in the selection of sustainable processes are energy input and pollutant emissions. In 2002, chemical manufacturing and petroleum refining consumed the most energy within the industrial sector [68] . Table 5.1 shows the energy consumption of 11 sectors, detailing the most energy intensive elements of manufacturing in comparison to the economic value of the final product. When it comes to the emissions of pollutants, processes involving combustion generally result in the highest emissions. Consequently, avoidance of combustion processes will most likely increase the sustainability of a productâ&#x20AC;&#x2122;s manufacturing. Table 5.2 contains the data on emissions by sector for 2002.

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CHAPTER 5. MACHINING AND TOOLS

Table 5.1: Sector energy consumption and energy intensity in 2002 [68] Sector

Energy Consumption (TBtu)

Energy Consumption (103 Btu/$= KBtu/$)

Chemical manufacturing

3,769

8.5

Petroleum refining

3,086

16.1

Pulp and paper (forest)

2,361

15.2

Iron and steel

1,455

27.8

311

Food manufacturing

1,116

2.6

336

Transportation equipment

424

0.7

Cement

409

332

Fabricated metal products

387

1.7

321

Wood products (forest)

375

4.2

3313

Alumina and aluminum

351

12.2

3315

Metal casting

157

5.6

NAICS 325 324110 322 331111

327310

Table 5.2: Energy-related CAP emissions by sector in 2002 (units TPY: tons per year) [68] CO (TPY)

NOx (TPY)

PM10 (TPY)

SO2 (TPY)

NH3 (TPY)

VOC (TPY)

Energy-Related CAP

CAP Emissions

Alumina & aluminum

6,776

13,036

474

51,176

1,234

72,736

538,841

Cement

15,674

11,636

668

12,943

553

41,477

544,501

325

Chemical manu.

213,176

220,183

10,510

279,403

4,474

11,377

739,123

1,536,183

311

Food manu.

70,848

73,073

7,218

90,203

860

5,522

247,724

395,289

331111

Iron & steel

125,574

45,779

6,858

43,589

1,543

4,465

227,808

850,644

332813

Metal finishing

111

374

3315

Metal casting

1,790

2,295

150

759

207

5,225

72,645

33611

Vehicle manu.

2,456

3,720

167

2,235

196

8,801

48,761

3363

Vehicle parts manu.

201

492

131

867

7,778

324110

Petroleum refining

46,942

117,470

8,738

108,189

1,366

16,133

298,838

788,985

322

Pulp and paper

195,218

184,514

17,617

303,285

1,215

19,099

720,948

1,173,568

321

Wood products

101,106

26,369

17,271

3,658

34,791

183,285

289,727

Shipbuilding/repair

186

866

1,150

121

2,419

5,520

779,958

699,461

69,788

896,669

9,656

93,830

2,549,362

6,252,816

3313 327310

336611 Total

CHAPTER 5. MACHINING AND TOOLS

Sector

NAICS

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CHAPTER 5. MACHINING AND TOOLS

5.2.2

Plant and Machining Selection

As important as the process chosen for the product manufacturing is, the plant which executes this process can be equally important. Within a given facility, energy can be lost in many ways. In the tour of a vendor facility, an engineer should check to make sure multiple aspects are properly addressed to restrict energy loss. The elements include fuel and electricity distribution, as well as steam pipes, traps, and valves. The magnitude of energy losses in the above can range from 3 % to 40 %; with the largest losses typically in steam pipes (up to 20 %) [68] . Other elements worth consideration are the machining tools themselves, as inefficiencies in equipment utilized for preprocess and manufacturing processes can lead to large energy losses. This includes motors, mechanical drives, process heaters and coolers, etc. Compressors are especially inefficient, often losing as much as 80 % of energy inputs, while pumps and fans typically lose 35 % to 45 %, compared to typical motor energy losses of 5 % to 10 % [68] .

Elimination and Recapturing of Waste â&#x20AC;&#x153;Waste elimination is one of the most effective ways to increase the profitability of any business. Processes either add value or waste to the production of a good or serviceâ&#x20AC;? [69] . This section will focus on both increasing sustainability in the manufacturing process regarding recycling techniques and designing for raw product use efficiency. In the ideal manufacturing process for a product, a plant would take in a certain amount of raw material, combine that with the energy used in the creation of the product, and export finished goods with no excess material or waste that needs to be disposed. This is called lean manufacturing, and it originally derives from the Toyota Production System which focused on seven wastes in the common manufacturing process. Using lean manufacturing techniques has in some cases led to a 30 % reduction in operating costs [70] . These seven wastes are transportation, inventory, motion, waiting, overproduction, over processing, and defects [69] . The three wastes which will be explored in depth are: Inventory, Over Production, and Over Processing.

5.3.1

Inventory

Inventory can exist in three areas: raw materials, works in progress, or finished goods. All three represent capital that has not generated any value for the company. Reducing the amount of time that any item spends in inventory reduces funds that a company cannot use.

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CHAPTER 5. MACHINING AND TOOLS

5.3.2

Over Production

Over production is when a company creates more product than the custom actually demanded. This results in an inventory of finished goods.

5.3.3

Over Processing

Over processing is putting more work than in necessary into a product without increasing the value of the product to the customer. This is a waste of resources, time, and money.

5.3.4

Recovery of Materials and Energy

Overall, efficiency in the manufacturing process is one of the main themes combating these wastes. Taking those into account, recycling excess material and energy during the manufacturing process can help combat these wastes. The opportunity to gather excess material is in the beginning of most production processes, where mostly raw material is used. Gathering excess raw material, and either reusing it if it doesnâ&#x20AC;&#x2122;t require processing for reuse, or sending it to another plant for post-processing, can reduce raw material costs. This leads to an increase in sustainability, because there is a reduction in wasted material and increase in efficiency. Recovering energy in the manufacturing process can also increase sustainability. Combining simple processing steps, or any improvement that saves time on the manufacturing floor, reduces manufacturing time and energy required. Additionally, if there are any energy intensive processes that produce thermal energy, recapturing that energy and using it for climate control throughout a plant is a sustainable option. Combining these techniques with reduction in inventory, over processing, and over production will lead to a more efficient manufacturing process that will reduce overhead costs and increase sustainability. Recycling material and recapturing excess energy, and turning a manufacturing plant more towards a closed system of energy that imports raw materials and exports solely finished goods, is the ideal sustainability option.

Proper Procedures for Machining One vital aspect to the sustainability of tools and machinery is knowledge of proper techniques, maintenance and care needs, and safety standards. Understanding these basic principles will prolong use of each of the tools or machines. Improper use of a tool or machine can cause premature failure. This reduces sustainability by increasing the disposal rate of parts as well as increasing the resources used to acquire new tools or machines.

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CHAPTER 5. MACHINING AND TOOLS While using tools and machinery it is important to understand the process or function they are providing. For example, when using a mill, the user must understand that the machine is going to heat up while drilling or cutting. Depending on the strength and density of different materials, the feed rate and bit speed must be adjusted so that cuts may be made cleanly without damaging the machinery. It is natural for tools to dull over periods of use. It is vital that when a tool starts to dull, the user removes the tool and has it sharpened before continuing use. If the tools are not maintained sharp, they can become susceptible to catching and breaking or overheating, which can also cause failure. To prevent overheating of machinery and tools during usage, lubrication is important. For example, when using a mill it is vital to lubricate the bit or the piece of material being milled with oil. For large automated mills and other machines, water lubrication and cooling is often used to reduce friction and heat increases. Figure 5.1 shows water lubrication and cooling being used on an automated mill.

Figure 5.1: Water Cooled and Lubricated Mill [71] Finally, when a tool or machine does fail, safety during maintenance is also important to ensure no further damage is done. The most important part of this is turning the power off on any machinery so that there is no chance it turns on and either harms itself or the user. For tools, while power is not involved, it is important that they are used for their designated jobs. For example, a file should not be used as a lever and a screwdriver should not be used as a chisel or a hammer as this will dull the end and ruin the usability of the head, necessitating replacement and decreasing sustainability. These are just a few ways knowledge and implementation of correct usage of tools and machinery can increase sustainability.

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Chapter 6 Sustainability in Production Within production, there are a number of different strategies to increase sustainability. This chapter focuses on sustainability strategies regarding different production methods, six sigma application, lean production strategies, demand forecasting, and inventory management. Additionally, the end of the chapter gives examples of conscientious production. After reading this chapter, it is our hope that strategies for sustainability in production can be applied for many industries and situations.

Sustainability in Different Production Methods Manufacturing plays a major role in overall sustainability due to its size and scale. Manufacturing processes account for approximately one third of the worldâ&#x20AC;&#x2122;s energy usage and is responsible for 36 % of the worldâ&#x20AC;&#x2122;s carbon dioxide emissions. [74] Due to the major role manufacturing plays in both resource consumption and emissions it is important to improve processes so that they more sustainable. Common manufacturing processes include the production of Plastics and production of metals like steel and aluminum. All these manufacturing processes can be made more sustainable by limiting harmful elements in the production and reducing the energy required to perform the process.

6.1.1

Plastics

Currently the production of most fossil-fuel based plastics relies upon solvents which are toxic and dangerous for both humans and the environment. Some examples of the toxic chemicals used in the production of plastics are benzene, for polystyrene plastic, and bisphenol A, for polycarbonate. [75] These toxic chemicals used in the production of plastics are not sustainable due to the risk they pose to the manufacturers and the environment. Clearly it would be more sustainable and therefore better to use methods for plastic production which minimize or 71

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CHAPTER 6. SUSTAINABILITY IN PRODUCTION stop the use of toxic chemicals. This could be done for many components of the plastic manufacturing process. A sustainable manufacturing method would attempt to remove toxic chemicals from plastic product and the solvents used to create the plastic. Other sustainably improvements in the plastic manufacturing process include using solvents and creating products that are degradable after use and implement safety measures which help to prevent dangerous accidents. One example for an improved plastic production method would to use a renewable source like polylactic acid from corn instead of the more common petroleum. [76] Overall a sustainable plastic manufacturing process would be one which avoids unnecessary toxic chemicals and utilized renewable recourses as much as possible.

6.1.2

Metals

For the sustainability in the manufacturing of metals it is important to try to minimize energy consumption and waist for that given process. The production of steel is one of the major metal manufacturing industries. The chart below list several forms of steel production and the energy required to perform that process on one ton of steel. [77]

Table 6.1: Energy Consumption for different Steel Production Methods (GJ/ton product) [78] Process Liquid Hot Metal Liquid Steel (BOF) Liquid Steel (EAF) Hot Rolling Flat Cold Rolling Flat

Actual Requirement 13 to 14

Actual Minimum 9.8

Difference (%) 25 to 30

Practical Minimum 10.4

Difference (%) 20 to 26

10.5 to 11.5

7.9

25 to 31

8.2

22 to 29

2.2 to 2.4

1.3

38 to 46

1.6

24 to 33

2.0 to 2.4

0.03

0.9

55 to 63

1.0 to 1.4

0.02

98 to 99

0.02

98 to 99

From this chart it is easy to see that there is lots of room for improvement in energy conservation of the steel making process. Reducing energy consumption would not only improve the sustainability of the process but also help to decrease the monetary cost of implementing that process. The desire to improve the efficiency of the manufacturing process by reducing energy consumption also applies to all other forms of metal manufacturing. Overall 72

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CHAPTER 6. SUSTAINABILITY IN PRODUCTION improving these processes would be a big step toward more sustainable manufacturing. The other major factor in sustainable manufacturing for metals is recycling. This is best illustrated by aluminum. Because creating aluminum from Bauxite consumes massive amounts of electricity, recycling used aluminum is quite effective. It takes 95 % less energy to recycle aluminum that it does to create aluminum for raw recourses. [78] By recycling used metals back into metal manufacturing energy costs are reduced which makes the process as a whole more sustainable.

Six Sigma The business strategy Six Sigma is a very effective methodology that many companies use to achieve a certain level of productivity and sustainability in production. Six Sigma (also abbreviated 6σ) in a literal sense stands for the production of quality products within six deviations from the norm. In other words, the goal of Six Sigma is that 99.9997 % of the time during production, a product will be made sans defects. Founders of the Six Sigma Academy, Mikel Harry, Ph.D, and Richard Schroeder, gave their definition of Six Sigma, stating, “It is a business process that allows companies to drastically improve their bottom line by designing and monitoring everyday business activities in ways that minimize waste and resources while increasing customer satisfaction.” While on the surface it seems like Six Sigma is a simple way to fulfill what should be an obvious goal for a company, it is in fact a long-term process that requires change throughout the entire company [79] .

6.2.1

Origins of Six Sigma

Six Sigma is a way in which product variation can be measured and either reduced or eliminated. While the origins of the techniques used in Six Sigma can be traced to Carl Gauss who introduced the normal curve in the 1800s, not until the mid 1980s did Bob Galvin achieve mainstream attention for reducing product variation with his company, Motorola, by using these methods. Galvin realized that it could be possible and just as reliable to measure products for defects on the millions rather than on the thousands and at the same time offer tremendous savings for his company [80] . Within the first ten years following Galvin’s implementation of Six Sigma, Motorola experienced an increase in sales by five times, nearly 20 % of profit growth per year, a 21.3 % stock growth per year, and an estimated savings of $14 billion [79] . Because the goal of Six Sigma is to reduce costs and defects in production, it should be clear how a company can save money and provide a level of sustainability: efficiency in production eliminates excess waste in the form of useless products and causes only the necessary materials and resources to be consumed during the creation of goods.

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CHAPTER 6. SUSTAINABILITY IN PRODUCTION

6.2.2

Certification and Use of Six Sigma

For a company implementing Six Sigma, there are four main levels of certification that can be achieved by employees, as shown in Table 6.2.

Table 6.2: Six Sigma Levels of Certification [81] Six Sigma Certification Level Yellow Belt

Green Belt

Black Belt

Master Black Belt

Description Initial exposure to company specific methodologies; basic understanding of system provided Approximately three years of experience; analyze and solve problems under Black Belt supervision Implement Six Sigma related policies and are certified to train and mentor employees. Black Belts with several years of experience; quality experts in several areas of the company; mentor Black Belts.

In order to increase the output a company is able to produce without losing any of the quality in production, the process has to begin with sound management strategies. While the basic foundation for Six Sigma is the same for all industries, a company will find the most benefit when they customize their companyâ&#x20AC;&#x2122;s processes to follow Six Sigma guidelines most appropriately for them and not exactly copy what another company has done. Six Sigma can only be successfully implemented with a cultural change that permeates from the top executives, down to the entire company. Because of this, any change will take time, and it is important that all employees of a company become well-versed in the Six Sigma methodology to ensure everyone is working toward the same goal. While it is true that Six Sigma can create an increase in revenue by decreasing cost and cycle time, at its core it is a data-driven management style seeking perfection. If implemented correctly, Six Sigma can be a powerful tool for any engineer in making a company more sustainable due to a reduction of wasted resources.

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CHAPTER 6. SUSTAINABILITY IN PRODUCTION

Lean Production 6.3.1

A Brief History

Lean Production (also known as Lean Manufacturing or Lean Enterprise) is a relatively new term for a practice that began to evolve many years ago [82] . Henry Ford’s development of the assembly line technique for mass production by the standardization of tools and parts is considered to be the basis of lean production. Ford utilized the principles of Scientific Management originally by Frederick Taylor in the 1880’s and 1890’s, which are also the founding principles of lean. Taiichi Ohno, an executive of Toyota Motor Company and the father of the Toyota Production System (TPS), further refined Ford’s system. It is the Toyota Production System (developed between 1948 and 1975) that became known as lean manufacturing in the United States. Ohno came up the seven wastes of manufacturing [83] . A waste is anything that is done do a product that does not add any value to it [84] . The seven wastes are [85] : 1. overproduction – things made earlier, faster, or in larger quantity than required by next stage, 2. time on hand – good are not in transport or being processed, 3. transportation – products should ideally only be moved when being delivered to a customer, 4. processing itself – any work is done to a product that is not required by the customer, 5. stock at hand – represents capital that has not yet produced an income, 6. movement – moving people or equipment that are producing a product, and 7. making defective products – costs accrued from redesign, recalls, and lost time. The other main objectives of TPS are to design out overburden and inconsistency. Ohno and his team were inspired to create the TPS after visiting several of Ford’s automotive plants and questioning the necessity of the extremely large inventories and uneven amount of work different departments had on different days. After a visit to a grocery store where they observed a policy of only ordering inventory to restock shelves after the food was bought by customers, they were inspired to mimic this policy in their manufacturing facilities. They reduced their inventory to only a level that it employees would need for a set amount of time, and then reorder. This policy came to be known as the Just-In-Time inventory system. It wasn’t until the 1990s when the term “lean manufacturing” was made common. A team of researches from MIT made the term famous in their book “The Machine that Changed the World.”

6.3.2

Implementation of Lean Production

The main idea of lean production is achieving perfect work flow. This means getting the right amount of things to the right people at the right place at the right time. The steps to 75

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CHAPTER 6. SUSTAINABILITY IN PRODUCTION creating a lean system are simple in concept. First, one must design a simple manufacturing system. The simpler the system is, the less room there is for any of the seven wastes. Then, it must be recognized that there is always room for improvement. Even when a system is working well, there is always something that could be done better. It is this mindset of continuous improvement to eliminate all waste that makes lean production so efficient. It is not a one time fix, but an on-going and continuous process that leads to a more efficient and more profitable production system. A lean system can improve the quality of a product, eliminate all types of waste, reduce time required to finish a process, and reduce the total cost it takes to manufacture a product. [86]

Demand Forecasting Management and Inventory Management Successfully forecasting demand and managing inventory levels is an important step to running a sustainable operation. Both of these strategies attempt to regulate production in a way to increase sustainability, efficiency, and profitability of the business.

6.4.1

Demand Management and Forecasting

The purpose of demand management and forecasting is to allow for planning of resources, equipment and people to meet customer satisfaction. Accurate planning, however, also ensures that extra supplies are not produced and resources not wasted. By obtaining a more accurate demand, resources are conserved and production is more sustainable. Nevertheless, determining accurate forecasts for demand can be a complicated and imprecise science. As such, there are a number of different factors involved in the forecasting process. Demand management is broken into strategic forecasts, which tend to be long-term forecasts containing strategies for meeting demand, and tactical forecasts, which are day-to-day operations [87] . Additionally, it is important to understand the difference between dependent demand, caused by other products, and independent demand, not correlated to other products therefore more difficult to predict. Predicting demand can be accomplished through four different strategies. The first is qualitative techniques, which use knowledge of experts in the industry. This is most useful when the product is brand new and there is no predicate knowledge for the demand. To accomplish this forecasting, market research, panel recommendations, historical analogies and the Delphi methods must be used (For more information see The Delphi Book) [88] . Another strategy for predicting demand involves time series analysis, which involves using past demand to predict the future demand. This serves use in short-term, medium-term, and long-term applications for forecasting. The third strategy involves causal relationship forecasting, which uses independent variables other than time as leading indicators to forecast demand. The complication with this method results from determining which variables are actually real causes for fluctuations in demand [87] . Finally, an Enterprise Resource Planning (ERP) System can be used (For more information see this website: What is ERP? [89] ). 76

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CHAPTER 6. SUSTAINABILITY IN PRODUCTION

Figure 6.1: ERP System Function Map [90]

This computer system links all areas of business, from manufacturing to sales, purchasing to logistics. This reduces the amount of hard-copy information that must be transferred, increasing the sustainability of a business as a whole. It also allows for more accurate information sharing between parties, reducing scrap and overproduction which may occur, ultimately reducing waste from production processes. Consequently, the ERP System can be used to increase sustainability of a companyâ&#x20AC;&#x2122;s manufacturing as well as the entire organization as a whole (Figure 6.1) [89] . ERP Systems are used in operations of a company, focusing on materials management, plant maintenance, quality management, production planning and control, and sales order management. Through application in these operations, raw material flow is more closely regulated, reducing waste. Additionally, machines are properly serviced at regulated intervals, increasing the working life of the production equipment. There are a number of vendors for ERP Systems, including SAP, Oracle, JD Edwards, i2 Technologies, Lawson and Sage. Although ERP Systems are very costly to implement initially, they can have benefits in terms of efficiency, profitability, and also sustainability by regulating processes, reducing waste, and increasing equipment longevity.

6.4.2

Inventory Management

One such aspect of regulation from ERP Systems is inventory management. By keeping sufficient inventory, customers are kept satisfied and money is not lost on potential sales which are unmet. On the other hand, if inventory is too high, money is lost due to holding costs and antiquated inventory. In certain industries, when too much inventory is kept, the inventory spoils either literally or simply due to lack of demand from rapid technological advancement. This situation results in wasted company resources as well as material re77

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Figure 6.2: Forms of Inventory [91]

sources used to produce the product. Consequently, inventory management is an important aspect to maintaining a sustainable business. Inventory Management is the planning and controlling of inventories to accurately meet competitive priorities of a firm. These decisions are made on macro- and micro-inventory levels. Macro-inventory decisions include the location of holding inventory (manufacturers/suppliers, warehouses/distribution centers, retailers) and the types of inventory to keep (raw materials, WIP, finished goods) as shown in Figure 6.2 [87] . These decisions are influenced by the objective of the companyâ&#x20AC;&#x2122;s production processes. Micro-inventory decisions include when to order items, how much of each item to order and how much safety stock to keep. Consequently, micro-inventory decisions have more sustainability implications than macro-inventory decisions, although both are important. The objective of micro-inventory decisions is to minimize the overall cost of keeping inventory. Most importantly to sustainability objectives, holding costs of spoilage, scrap, and wasted material, must be reduced [87] . Consequently, inventory management and demand management/forecasting go hand-in-hand in the evaluation of production decisions. Inventory management decisions are based on accurate demand forecasting in order to know the proper safety stock and holding amounts. In the same way, demand management is based upon lessons learned from previous inventory management results. Both concepts, however, are crucial to production decisions in terms of sustainability. By reducing the waste of overproduction and inaccurate forecasting, in essence reducing sustainability holding costs, a companyâ&#x20AC;&#x2122;s production process can be made more sustainability, ultimately also leading to higher efficiency in production and higher profitability.

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Manufacturing Conscientious Design - Examples of Conscientious Production Many companies are reviewing their manufacturing in an effort to trim away any unnecessary waste and to improve the sustainability of their manufacturing processes. Some companies have developed innovative new methods of managing their manufacturing that have put them ahead of the competition. This section will examine these companies that are leading the way in developing conscientious, eco-friendly, manufacturing practices and look at how they got to the front of the pack.

6.5.1

Suncor

Suncor is a Canadian oil company with a commitment to environmentalism. Suncorâ&#x20AC;&#x2122;s dedication to going above and beyond in the field of environmentalism has earned the company a membership in the Dow Jones sustainability index. Suncor was also named the top performer in a survey of 23 global oil companies by Jantzi Research. Suncor has improved the amount of oil it extracts per ton of greenhouse gas emissions by 25 % since 1990. Using its innovative Zero Liquid Discharge system, Suncor also plans to double oil production by 2012 without increasing the amount of water used. The Zero Liquid Discharge system works by passing the saline water (a byproduct of the steam injection mining process) through a pair of evaporators. These raise the concentration of dissolved solids in the water sufficiently that a rotary drier can separate the solid from the liquid. All of the water is then condensed and returned to the steam plant. Using this system, Suncor recycles 96 % of the water at its MacKay River in-situ facility. [92]

6.5.2

Rio Tinto Alcan

Rio Tinto Alcan is a Canadian aluminum maker that employs 68,000 people. Since 1990, Alcan has reduced its greenhouse-gas emissions by 25 % while simultaneously increasing production 40 %. Alcan has shown a commitment to sustainable manufacturing by investing in efficient, clean manufacturing processes. Alcan also works closely with the buyers of its products to maximize the return on their investment, constantly making changes to their manufacturing process to reduce waste and maximize efficiency. [93]

6.5.3

S.C. Johnson

Each year S.C. Johnson products worth a total of $8.75 billion are sold in more than 110 countries. By aggressively pursuing renewable energy projects such as wind energy, landfill gases, and palm shells, S.C. Johnson cut its energy usage 32 % between 2000 and 2009. S.C. Johnson has also recently made an effort to reduce the amount of harmful substances used in the manufacturing of several of its products. On its way to putting a Greenlist label on 79

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CHAPTER 6. SUSTAINABILITY IN PRODUCTION its Windex and Saran Wrap products, S.C. Johnson eliminated over 1.8 million pounds of volatile organic compounds from Windex and 4 million pounds of polyvinylidene chloride from Saran Wrap. [94]

6.5.4

General Electric

General Electric is a company at the forefront of innovative, eco-friendly, engineering. General Electric is involved with dozens of projects ranging from the new GEnx aircraft engines, which run 15 % more efficiently than the last generation of GE engines and over the next 20 years are estimated to emit 77 million fewer tons of greenhouses gasses than the engines they replace, to an innovative cooling system that cuts cooling costs by 35 % by freezing ice at night when energy is cheap and using the energy during the day to keep buildings cool. General Electrics lists four key words on their webpage: imagine, build, solve, and lead. By following these simple ideas, General Electric has become one of the largest companies in the world and a powerful force for sustainable engineering. [95]

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Chapter 7 Assembly and Disassembly Planning and accounting for manufacturing processes improves a productâ&#x20AC;&#x2122;s sustainability. As discussed in the previous two sections, how a part is designed, which tools and methods were selected, use of proven production methods, and production forecasting and inventory can significantly impact sustainability. However, assembly and disassembly of parts also plays into sustainability via part reduction, ease of assembly for assemblers with minimum tools required, and ease to get to fundamental material parts that are obsolete and need to be recycled. Considering these and many other sustainability factors, the selection of the connection method needs to balance these factors along with cost. Common, built in, and temporary fasteners, adhesives, and conscientious designed connections investigated in this chapter excel in some factors and hinder others. Choosing of the correct fastening method will improve sustainability.

Common Fasteners Fasteners are among the most common means of joining materials together. Each serves a different purpose, and they are used in almost all appliances and objects. Among these fasteners are bolts, screws, nails, pins, clamps, washers, and rivets. Bolts are made from one material throughout, usually a hardened metal. This allows them to be easily recyclable after reuse has rendered them useless. However, this cycle of reuse has a large time span due to the durability of both bolts and nuts. Bolts and nuts, both normal and winged, are more expensive than screws, as they are used in heavier duty applications. Screws are made of one durable material throughout, they can be reused multiple times until their integrity is compromised, after which they can be recycled. If the nail is not damaged upon extraction, it can be reused multiple times. However, extraction tends to bend the nail, compromising its ability to be used again unless they are unbent again. Theyâ&#x20AC;&#x2122;re overall recyclable since they are made from metal. Pins are similar to nails, in that they are reusable and recyclable, as they are made from a single material, usually metal or plastic. Clamps can be made of a combination of materials, usually plastic or metal, 83

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Figure 7.1: Different snap fit types for disassembly [98]

making them recyclable. Due to their nonpermanent nature, they are also reusable with a long fatigue life. All the materials that washers are made of are recyclable, and as long as the washer is not damaged from high bolt pressures, they can be reused. Rivets are not reusable, as to disassemble them, they need to be drilled out. The rivet itself is made from one material, making it recyclable, but if used, the materials it binds must be of the same material in order for it to be recyclable.

Built In Fasteners Built-in fasteners have a direct impact on the sustainability of a product. They impact both the ability of the product to be recycled and the amount of energy required to make the joint. If components are permanently bound together it can become much more difficult to recycle the part if only one of the two components were recyclable. However these fasteners are critical decisions in the design process and must be considered. Of the listed built-in fasteners, snap fits are the most sustainable product because of the products that use them. The ability of the snap fit to be disassembled is dependent on its design. If the hook is rounded then the joint is meant to be disassemble, but if the hook is square the joint is intended to be permanent. Figure 7.1 demonstrates four designs, three of which can be disassembled. [96;97] Press fits are an inexpensive joining process that relies on friction forces and plastic deformation. Due to these requiremenets the material choice is critical in this joint. This process involves a greater force than other joints because of the energy required to force the shaft into the bearing. Removal of the shaft from the 84

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CHAPTER 7. ASSEMBLY AND DISASSEMBLY bearing often results in the failure of one or both of the components. Thus press fits are irreversible. [99] The amount of energy necessary for welding is dependent on both the material used and the welding method. This process has often been automated to increase production speed but it is still performed manually for more custom products. This processes creates one of the strongest bonds between materials. [100]

Temporary Fasteners When assembling parts, a need for temporary fasteners may arise. These fasteners may either be used to hold components together during the assembly process or to temporarily hold components together in packaging so that the product will stay in place during shipping from the manufacturer to the consumer. Some examples of the latter include toys, tools, or appliances which are held in place to the packaging either by zip ties, tape, rubber bands, staples or even sometimes screws. The decision for the best temporary fastener should always be one that requires the least amount of material but is still able to secure the components to their packaging. The reason for this choice is because the consumer will immediately discard these parts, usually without recycling them. Zip ties provide a strong connection that will not come undone unless the head is cut off or broken. For this reason, zip ties cannot be reused. Twist ties usually contain a thin metal wire wrapped by a thin layer of plastic or paper which means that additional resources will be required to recycle them. Biodegrable twist-ties are available at this time. Rubber bands can easily be reused by a consumer, until the rubber band breaks, and should be considered as a temporary connection more often. Staples should be limited since they will be thrown away as soon as the staple is removed and cannot be reused. Screws and clips usually require more material, either plastic or metal, in order to provide a strength comparable to that of zip ties. To eliminate waste, these screws or clips should be accounted for in the product assembly, such that the consumer does not throw them out after a single use.

Adhesives The sustainability of glue, tape and caulk is dependent on both the materials that are used in their construction and also on the way they are used. Often, a petroleum base is used for adhesive products. All natural adhesives made from plants and animals are available but may not be as strong or consistent. Some glues are a mix of various chemicals each needing to be shipped from its origin to the plant and eventually to the consumer. Adhesives are generally permanent, making the products they are used in difficult to disassemble and recycle. Improvement in technology to make strong natural adhesives whose bonding can be 85

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CHAPTER 7. ASSEMBLY AND DISASSEMBLY reversed affordable and reasonable for use would greatly improve the industries sustainability. Overall, the sustainable use of adhesives must be considered in terms of their sealing benefits versus the negative impact on the environment from their production and permanent bonding qualities. Important Sustainability Considerations of Adhesives: • Use correct amount of adhesive. • Take into account the overall impact of permanently joining materials together. • Inspect the material basis of the adhesive with regards to sustainability. Glue can be made with all natural material(plant and animal compounds) which increases sustainability. Often synthetics are used for consistency and to strengthen bonds. Glue is light weight, so it may be used to reduce weight in cars and increase gas mileage. [101;102;103] Tape has the same sustainability points as glue, but it also has an extra paper or plastic component connected to the adhesive. Tape is generally used as a temporary fastener, thus it should be designed for single use. Caulk often has a petrochemical base, meaning they are based off of finite natural resources. Some contain heavy metals which reduces their sustainability. Caulk can cause air pollution through volatile organic compounds(VOCs). In certain cases, caulk may reduce energy consumption due to sealing up places where leakage may occur(for example, caulking can improve a home’s insulation). [104;105]

Designed Assembly Connector Concepts Previous fastening types allow for a fastener to be added to the already existing part. However, parts can also be designed with these connections in mind rather than as an afterthought. Outlined and explained below are methods and examples by which designs can be improved by eliminating confusion, ambiguity, assembly time, and worker injuries due to poor assembling ergonomics and part handling. Kenneth Crow, President of DRM Associates, created an online guideline for manufacturing and assembly design techniques. [106] . He discusses mistake-proof assembly designs, considering part orientation when designing, incorporating the worker into design considerations, and considering modular parts within these guidelines.

7.5.1

Mistake-Proof Assembly Parts

Reduce the number of errors in assemblies by making the assembly process unambiguous. Crow calls out six concepts to mistake proof an assembly [107] : 1. Elimination: eliminate errors by combining tasks or components into a single or fewer part thus eliminating the need for assembly of multiple or more parts. 2. Replacement: replace unreliable assembly processes with reliable and consistent ones. 86

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Figure 7.2: These wood circular symmetric pins can be installed with any rotation [108]

3. Prevention: prevent errors from happening by engineering the impossibility of a mistake happening. 4. Facilitation: make the process easier by combining steps or utilizing certain techniques. 5. Detection: utilize sensors and check points to alert and fix errors before the error propagates with further assembly processes. 6. Mitigation: protect for when errors do occur such that the product will not fail. Color coding is method used to prevent mix-ups, facilitate an easier process, and provide an easy method for detection of errors. Thus these concepts can overlap.

7.5.2

Oriented Parts and Oriented Handling

Remove ambiguity and thus errors by using asymmetrical shapes to help align parts. • If using symmetrical parts, try to make as many axes symmetrical as possible. • If using asymmetrical parts, emphasis the asymmetrical features for easy recognition and thus will be oriented and inserted correctly. Figure 7.2 shows symmetrical (circular wooden) pins and Figure 7.3 shows asymmetrical (computer) ports. The symmetry of the circle makes it obvious that this piece can be inserted in any rotation. However, the asymmetrical ports makes it obvious that it can only be inserted at a specific rotation due to the changes in length and shape as well as differentiates one connetor from another. • Facilitate insertion by providing guide surfaces or features. Features could include hole patterns, shapes, and notches as exemplified in Figure 7.4. Adjustable height tables generally have a pin release system with aligned holes to ensure a level table at specific heights. These incremental positions allows for only one orientation, where as a latch that tightens around a slipping inner beam (an example would be a camera tripod leg that can be adjusted to any length of the leg) allows for several non-incremental configurations. With the non-incremental configurations, there is a greater chance that a table would not be level than with an incremental configurations. 87

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Figure 7.3: These asymmetrical computer ports do not allow incorrect connectors or incorrect orientation of the connetor which removes ambiguity [109]

Figure 7.4: Notches and hole pattern angles only permit one orientation for assembly [110]

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Figure 7.5: Table top utilizing incremental pins to keep table level while offering varying height options [111]

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CHAPTER 7. ASSEMBLY AND DISASSEMBLY • The ideal piece for an assembler to work with is light and has flat, parallel surfaces such that it is easy to grip, but is not too thin or too small which would require finer motor skills and increase handling time. • Assembler safety must be considered during handling of objects with sharp edges, burrs, or points. These areas are also the first to show signs of damage or wear. • Fragile, slippery, and sticky pieces are not cost or time effective. They break easily which would require more parts be made for safety purposes. Slippery or sticky lubricants, treatments, coatings require cleaning treatments to remove these substances which can be costly and time consuming.

7.5.3

Ease and Efficiency of Assembly Design

Certain assembly methods take more time and effort thus incurring a higher cost. By eliminating time consuming (threaded fasteners compared to snap fits) or effort taxing (fine detail work) processes , cost is reduced and the assembler’s ergonomic condition is improved. Connections can be designed to eliminate parts. This makes shipping easier due to less materials needing to be placed in the box and taking up space within the box. For example long poles can have threaded ends to be connected without the use of extra parts which incur a higher cost. Standardizing fasteners also saves time since the assembler does not need to find a specific fastener. Guide features such as chamfers, tapers, and radii help align parts for insertion. Beginning with a large part and subsequent parts added on top of the other allows for easy assembly since the parts do not need repositioning. Simple hand assembly is easier to automate than complex hand assembly. Automation produces more consistent and reliable products with higher quality.

7.5.4

Modular Parts within Products

Modular parts provide a cost benefit by reducing the amount of expensive tooling. Modular parts serve as a interchangeable building block where parts can be added such to meet specific needs without creating a new part. Vacuum end attachments provide different air flows for specific flooring, yet they all attach to the same tube and vacuum. It would be impractical to buy a vacuum for carpeted floors and a vacuum for tiled floors. By building the same frame for several similar products and then adding extra small internal pieces to accommodate specific needs can be a significant cost savings. Figure 7.6 shows a spacer added to a hair dryer’s casing to accommodate a smaller motor for the United States. The spacer would not be used for a larger motor used in Europe where the electrical output differs from the United States.

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Figure 7.6: This specific spacer was used to allow for multiple motor sizes to fit within the same case molding

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Chapter 8 Packaging One significant aspect of the overall sustainability of a manufactured product is packaging. In this chapter, strategies to create cost-effective and cost-reducing sustainable packaging are highlighted, with examples given of successful and ongoing efforts in current companies. The guidelines address topics such as reusability and recyclability of packaging materials in striving towards closed-loop systems. Important elements include package design, choice of materials, package production, and life cycle impacts. Additionally, the section contains information on widely-debated issues regarding sustainable packaging, such as the benefits of plastics versus paper, for informed decision-making. This chapter is broken down into three main subsections: general guidelines for sustainable package design, food and beverage packaging, and consumables packaging.

General Guidelines for Sustainable Package Design Following below is a list of primary principles or questions to consider for designing packaging with sustainability in mind, accompanied by several innovative examples. Overall System [112] : • Are there changes in the system itself (for example, the primary, secondary, and tertiary packing, as well as the sourcing, transportation, and distribution modes) that allow for more efficient packaging? • Consider possibilities for making the process suit a sustainable design, rather than simply limiting the design by current processes. • Consider the entire system of packaging and assess where the greatest improvement can be made. Design for Life Cycle Objectives and Ideology Promotion [112] :

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CHAPTER 8. PACKAGING • Consider options for life cycle end of the packaging, reusing, composting, or recycling? Consider local waste management strengths and weaknesses in this choice. • Design for easy disassembly • Make identification of different materials easily manifest through texture, colors, etc. • Stewardship: Use packaging to promote sustainable attitudes. • Rethink aesthetics: Flaunt the uniqueness of recycled material in a positive light, rather than hiding it. German designers B¨ar & Knell create products from recycled plastic packaging that flamboyantly harness the cultural and historical variety in materials, and use them in colorful and originally aesthetic ways. Figure 8.1 is an assortment of kaleidoscopic-like lamp covers. This same principle can be employed when creating new packaging itself from recycled material. Marketing green packaging can be an exciting aesthetic opportunity [112] .

Figure 8.1: B¨ar & Knell lamps [113] Material Usage [114] : • Consider alternative physical properties or principles to meet technical requirements. • Look for alternative materials that are environmentally friendly and satisfy or even improve the technical design. • Minimize package-to-product weight ratio: Make it lightweight. • Reduce material content (amount of material used). • Reduce material count (number of different materials used). • Reduce material waste during package production. • Reuse post-consumer material. • Minimize overall dimensions and void space in packaging. • Minimize package-to-product weight ratio: Make it lightweight. • Remove unnecessary or overly redundant components. 95

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CHAPTER 8. PACKAGING For instance, Harley Davidsonâ&#x20AC;&#x2122;s reusable steel packaging system for motorcycles, by Worthington Steelpac Systems, replaces wooden crates which were inferior in strength and often scrapped due to moisture, insects, and knots. The steel system is more reliable, 27 % lighter, and offers better protection for the motorcycle from damage and scratches. The design is made from 30 % to 100 % recycled steel and is also completely recyclable itself.

Figure 8.2: Harley Davidson reusable steel packaging [114] The waterproof paper envelope in Figure 8.3 is made from 75 % post-consumer newspaper with a 100 % recycled paper cover assembled with water-based glue, and uses woven strips of newspaper instead of bubble wrap to provide ample cushioning for fragile goods such as electronic items. The next package, the blue box, is made from over 78 % recycled paper, uses an inner corrugated fitting for larger fragile goods instead of filling extra void space with bubble wrap and loose-fill chips, and reduces storage space by 40 %. Finally, the battery packaging shown is an example of reducing material count, made from only a single cartonboard material and eliminating the vacuum-formed plastic cell.

Figure 8.3: Waterproof envelope [114] Another alternative for cushioning includes using air itself as an air-cushioned package with two outer low-density polyethylene (LDPE) plastic laminations for strength and puncture protection saves 90 % storage space, 99 % dumping cost in landfill, and essentially zero breakage according to testing. Finally, for product wrapping, a cellulose-based plastic film 96

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CHAPTER 8. PACKAGING such as the one shown may be a sustainable choice, as it is biodegradable, dissolves quickly in water under 50 ◦ C with no harmful elements, and is even edible.

Figure 8.4: Air-cushioned packaging [114]

8.1.1

Sustainable Packaging Metrics

There are two approaches for measuring the sustainability of packaging: isolating key metrics and Life Cycle Assessment tools which give more comprehensive and in depth analysis. The Global Packing Project produced and made available two excellent sources for measuring sustainability, the Global Protocol on Packaging Sustainability 2.0 and A Global Language for Packaging and Sustainability: A frame work and measurement system for our industry. [115] . The Global Protocol on Packaging Sustainability 2.0 provides a “dictionary” for describing sustainability metrics and indicators, whereas A Global Language provides the framework to use the terms to discuss sustainability. Together these are excellent resources to discuss indicators and metrics for analyzing the environmental, economical, and communal sustainability of a packaging design. Engineers must carefully choose which metrics they consider key indicators of sustainability, because many metrics are not independent and an improvement in one metric may actually reduce the overall sustainability. For example: “Design guidelines for packaging weight reduction would encourage a designer to combine materials in multilayer structures efficiently combining strengths of individual materials in order to save packaging weight. Such guidelines are in direct conflict with guidelines on recyclability, which would call for use of a single material in a packaging format which is easily identified, separated and recycled” [115] . Because of the problematic nature of isolating key metrics that indicate sustainability, the Global Packaging Project suggests a Life Cycycle Assessment, LCA, approach. Although this method takes much longer to properly perform, it gives a more holistic approach to the environmental impacts of using a specific package design. A 2010 report by The Industry Council for Packaging and the Environment lays out the best LCA tools available to the public [116] . Although these tools analyze environmental factors, they do not consider business and community factors, such as profitability of design and public safety.

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Figure 8.5: Optimum pack design 8.1.2

Product Safety

The key role of packaging is to provide product safety and ensure that the product reaches the customer undamaged. Generally, the product the packaging protects has a higher material and value worth than the packaging, and therefore, waste saved by under designing the packaging can actually waste more material. This concept is graphically described by Figure 8.5, produced by Innventia AB [115] . Current views of packaging waste are often associated with over packaging. Therefore, a balance between over packaging and waste through damaged products must be maintained. Consider the following items: • What are the modes of failure and how can they be prevented by packaging? • Are the failure modes well documented, and how much mechanical protection is actually needed? • Are packaging requirements well defined? Are you guessing what is wanted? See Target example [117] • Also, look at the support system; can the support system be redesigned so less protection is required at the packaging level?

8.1.3

Distribution

During distribution, sustainable packaging considerations should be made at each level of packaging. The three levels of packaging are shown in Figure 8.6 [115] . Primary packaging is the packing that is in direct contact with the product; secondary packaging is packing a number of primary packages together; tertiary packaging is used to transport the product from manufacture to retail. The best way to obtain efficient distribution packaging is 98

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Figure 8.6: Three levels of packaging

to design the product and packaging simultaneously. For example, stacked plastic chairs maximize packing efficiency by eliminating secondary packaging. Once product safety considerations have been made at primary and secondary levels, the sustainability of the appearance and how product information is communicated should be considered. Does marketing and information on packaging prevent proper recycling or lead to over packaging? Are there different ways to communicate information to reduce the amount of packaging or lead to proper recycling of the product? Tertiary packaging involves many product safety considerations. However, tertiary packaging provides greatest opportunity to improve sustainability by maximizing pallet efficiency, reducing weight and reusing packaging. Increasing pallet efficiency entails maximizing the number of products per pallet while maintaining adequate protection. Reducing the volume of the packaging and designing packaging for stacking greatly improves pallet efficiency. Reducing packaging weight is important because heavier packaging requires more energy during transportation. In tertiary packaging, the packaging is not in direct contact with the consumer product and therefore efforts should be made to find ways to reuse packaging. Consider systems for retrieving tertiary packaging for reuse. The WasteWise article has a list of resources and ideas for obtaining and using reusable packaging [117] .

8.1.4

Resource Recovery

Returnable Packaging A returnable packaging system involves the supplier recollecting the container from the consumer for reuse, often utilizing a deposit refundable upon return as a financial incentive. There are several benefits to a returnable packaging system. First, the process bypasses the energy and resources utilized in extracting and producing virgin material. Second, it saves the high energy and cost associated with recycling a container that has only experienced once cycle of use. Finally, the materials do not become part of the waste stream, as ideally the final cycle of the reused packaging is to then recycle it for remanufacturing, keeping the material permanently in the system and out of the landfills. Effectively implemented returnable packaging can be seen in examples such as the British milk delivery system and in Finlandâ&#x20AC;&#x2122;s glass and plastic bottling industry. It is estimated that British milk bottles are reused at least 12 times and Finnish glass beverage bottles up to 50 times. The procedure 99

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CHAPTER 8. PACKAGING in Finland has resulted in the lowest packaging waste per capita than any other European country. [112] Refilling Refilling involves the consumer returning to the point of purchase with an empty container and filling it from the supplierâ&#x20AC;&#x2122;s bulk container. Currently, it is more widely used in countries with less developed infrastructures and distribution networks, or in small-scale retailers. Due to hygienic regulations, some items such as medicines and certain foods cannot utilize this system. Still, potential for this system may most successfully lie in areas such as hardware and garden or home products. Another concern is that the operation of this system in bulk rather than individual item marketing means that product branding and promotion may be more difficult. However, the success of The Body Shop, one of the largest international cosmetic franchises, shows that implementation may be achieved through using container designs that become the companyâ&#x20AC;&#x2122;s trademark itself, rather than relying on graphic identification. [112] Composting Through the use of composting, biodegradable packaging materials may be turned into soil nutrients that aid tree and plant growth as renewable resources. Methods of turning this traditionally small-scale household system into an effective large-scale industrial system are largely still in development. The location of sites nearby both the source and the end user is of utmost importance, in order to minimize long-distance transportation. Composting is particularly valuable for contaminated packaging materials that would otherwise be problematic in other types of recycling, such as food wrappings. [112] Reconstitution (Recycling) Reconstituting, or recycling old packaged materials for use in other markets, can aid in maintaining a close-loop system when these materials are not reusable within the original market. Recent technological innovations now allow many companies to turn packaging waste into higher quality products that are both more useful and more attractive. Further, reconstituted packaging is not limited to production of new packaging material itself, but also an enormous variety of other manufactured products, such as furniture, construction materials, bridges, and even fleece sweaters. For instance, Patagonia is the first company to use polyethylene terephthalate (PET) plastic soda bottles to manufacture synthetic fleece clothing. For every 3,700 recycled 2-liter bottles, 150 fleeces are produced, a barrel (190 L) of crude oil is saved, and half a ton of toxic air emissions are avoided. [112]

100

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Figure 8.7: Packaging life cycles [112]

Food and Beverage Packaging The goal of this section is to identify the different segments within the food and beverage industry and then to give guidelines and recommendations for the packaging that would likely be used in each segment. Segments within the industry were identified by DuPont, which produces many of the materials used in packaging in the food and beverage industry [118] , with the added segment of the food service (restaurant) industry since it is itself a large industry and because it has its own specialized packaging. For each segment, the guidelines were based on the criteria for sustainable packaging as put forth by the Sustainable Packaging Coalition and their Design Guidelines for Sustainable Packaging [114] . Packaging should: 1. be beneficial, safe, and healthy for individuals and communities throughout its life cycle, 2. meet market criteria for performance and cost, 101

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CHAPTER 8. PACKAGING 3. 4. 5. 6. 7. 8.

be sourced, manufactured, transported, and recycled using renewable energy, maximize the use of renewable or recycled source materials, be manufactured using clean production technologies and best practices, be made from materials healthy in all probable end-of-life scenarios, be physically designed to optimize materials and energy, and be effectively recovered and utilized in biological and/or industrial cradle-to-cradle cycles.

In general, all types of packaging should satisfy the first criterion, but it is especially important for the food and beverage industry. All materials used should be safe and nontoxic, both during and after their intended useful life. Similar to packaging of medical products, great care must be taken to ensure that the packaging used is sanitary and nontoxic throughout its life cycle, including any adhesives used in the packaging. Also, the second criterion must be met. If a design does not perform as needed or is not viable financially, it generally will not be implemented. With regard to the third criterion, sustainability in manufacturing is considered in the manufacturing processes section of these guidelines. Sustainability in transportation is considered in the transportation section of these guidelines. Packaging as it relates to transportation will be considered for the seven segments. It should be noted that there are several times where the use of recycled plastic in packaging is encouraged. The Food and Drug Administration (FDA) has concerns about contamination of food by recycled plastic used in packaging. Because of this, if there is to be contact between the food and recycled material, the FDA requires that the manufacturer submit a “complete description of the recycling process,” test results that show the removal of possible contaminants, and a description of the use of the recycled plastic [119] . This additional requirement on the use of recycled plastic can increase the cost of the packaging. There is a positive, however, in using recycled plastics in that it greatly increases a manufacturer’s sources of packaging material in addition to improving the sustainability of the packaging. There are general guidelines for packaging that are applicable to all segments in the food and beverage industry, such as: • Minimize the amount of material used by minimizing the thickness and surface area of the packaging while meeting performance requirements. • Maximize the use of recycled materials in the production of packaging. • Design the packaging such that it fits together as tightly as possible to enable efficient stacking. This allows for a reduction in the amount of material used in transport packaging. The following are guidelines for designing more sustainable food and beverage packaging by segment.

8.2.1

Beverages

• Use materials that are biodegradable or easily recyclable. Limit use of paperboard cartons with wax or plastic liners because these are not universally recyclable. 102

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CHAPTER 8. PACKAGING • Reduce the amount of material used as much as possible. This could be through reducing the thickness and/or surface area of the packaging (ex. Aquafina’s Eco-Fina bottle which uses 50 % less plastic than previous bottles) [121] . • Especially applicable for beverage containers is the possibility of reuse, which would be the most sustainable practice. • Making beverage containers stackable and with a tight Aquafina’s Eco-Fina bot- fit reduces the amount of material used in transport tles [120] packaging. An example of this would be square milk jugs.

8.2.2

Dairy and Cheese

The most important aspect in dairy and cheese packaging is maintaining the freshness of the product, which is highly susceptible to molding and spoiling. These products are most commonly shrink/vacuum wrapped with plastic. • When considering packaging for dairy and cheese products, one should look into using recycled or easily recyclable plastics and/or biodegradable materials for shrink or plastic wraps. The use of paperboard would be desirable if there were no need for a wax or plastic liner, which would reduce recyclability. • Optimize the plastic wrap to be as small of a thickness as possible in order to conserve material. Some testing may be necessary to determine the minimum thickness to ensure freshness and sanitation during transportation, storage, and display.

8.2.3

Dry Foods and Snacks

• Snacks and dry foods provide a great opportunity to use recycled products because many of these packages are at least partially made from paper or paperboard, both of which can be produced from recycled paper. Even plastic films, bags, and molds used for structure and support can be made from recycled plastics. • Sun Chips uses a compostable (fully biodegradable) bag made from plant-based material [123] . This type of material could be used in other products that currently use plastic bags and films in their packaging.

8.2.4

Meats and Seafood

Compostable SunChips bag [122]

Like the packaging in many other segments, current packing methods for meat commonly employ shrink wrapping with plastic to ensure the meat is not contaminated. Additionally, 103

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CHAPTER 8. PACKAGING many forms of meat packaging also use foam meat trays to provide structure for the packaging. These trays are often made of polystyrene [124] , which is generally not recycled [125] , and when it is, it is downcycled.

• In place of polystyrene meat trays, one may want to consider the use of paperboard or other paper- or plant-based products that can be made from recycled paper and/or would be recyclable. For example, Dyne-A-Pack is a meat tray that is made of a plant-based biopolymer [127] . One could also investigate whether nonrecyclable components such as polystyrene meat trays are necessary at all.

8.2.5

Dyne-A-Pak biopolymer meat trays [126]

Produce

Current packaging for produce such as berries, carrots, lettuce, etc. consist of either hard plastic containers or plastic films or bags. Other produce, such as melons, apples, citrus fruit, etc. are not packaged in such a way but instead are packaged in the boxes they are transported in, though they may also use insert liners to allow for easier stacking [128] . • To improve the sustainability of produce packaging specifically, one may want to consider the use of mesh packaging (mesh bags, containers, etc.) instead of solid packaging. With the understanding that this may increase the cost of the packaging, the total use of material is greatly reduced [130] . • If possible, it is also desirable to display the produce in the same packaging as it is transported to eliminate one entire aspect of the packaging. This practice is much more acceptable and common in produce packSoft mesh aging than in other segments. bags [129]

8.2.6

Ready Meals

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SilviPak tray [131]

wood

Ready meals, commonly called “TV Dinners”, refer to frozen or chilled meals that come in an individual package. Packaging for these meals commonly consist of a tray (usually plastic) that holds the meal, and a box (usually paperboard) which houses the tray and meal during transportation and storage. There are some meals that are packaged with only plastic. Considerations for the packaging include the strength of the box for stacking during transport and storage, and the thermal properties of the tray as it experiences extremes in temperature during the cooking, pulp freezing, and reheating of the meal.

• If applicable, one may consider alternative materials for the tray, such as paper or wood pulp. The packaging company SilviPak has produced a tray composed of wood pulp. It should be noted that this particular tray is not made from recycled material and has a film barrier, though the tray is still highly recyclable and the film barrier can be easily removed [131] .

8.2.7

Food Service

Packaging is an important component of any restaurant operation, especially for “fast food” restaurants. There is a wide variety of packaging to be considered, such as “take out” containers, bags, sandwich wraps, disposable bowls, disposable cups, etc. Take out containers are commonly made from polystyrene, which is generally not recyclable. Bags and sandwich wraps, especially in fast food, are made from paper. Bowls may be made from plastics or paperboard. Cups are generally coated paperboard [132] . • Make take out containers from recycled and/or recyclable materials, such as paper, wood pulp, plant-based plastics, etc. • Use paper bags instead of plastic because paper is much more recyclable. Also consider making the paper bags from recycled paper. • Minimize the size of sandwich wraps to reduce the amount of material used. This has the added benefit of cutting costs. • Make disposable bowls from paper or wood pulp instead of plastic, similar to disposable cups. This greatly increases the recyclability and the use of recycled materials. • Use paperboard (preferably from recycled paper) for disposable cups over plastic if possible. • Avoid using individually-wrapped disposable eating utensils unless contamination is a concern. This greatly reduces the amount of material used.

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Consumables Packaging One of the biggest contributors to waste is the disposal of packaging for customer consumable items. These items fall under the class of products such as toothpaste, mouthwash, lotions, etc. The manufacturing, assembly, shipping, and disposal of this packaging contribute to one of the biggest costs to businesses as well. It is the goal of this document to provide overall sustainability guidelines for the packaging of these products while also making sure that its other functions such as containing, protecting, preserving, and advertising products are not compromised along the way.

8.3.1

Excess Packaging

One such problem that plagues the packaging of consumable items is the excess amount of packaging being used. Conventional theory states that an outer paperboard carton is needed for consumable items in order to preserve and protect the items that they are contained in. This, however, is not true because the outer carton can be eliminated while maintaining the productâ&#x20AC;&#x2122;s integrity. Warner-Lambert, a manufacturer of health care and consumer products made an effort to reduce the amount of packaging for its mouthwash product line. WarnerLambert decided to eliminate the glass bottle of mouthwash enclosed with corrugated and paper overwrap and decided to just use a plastic bottle instead [117] . By doing so, the company managed to eliminate over 19 million pounds of packaging per year, a 52 % reduction. By taking out unnecessary components, companies are able to reduce the impact they have in the environment.

8.3.2

Change in Design

Another problem that companies encounter when making more sustainable packaging for consumable products is their aversion to change the design of their packages. The shapes of the containers that these products are sold in have stayed relatively the same throughout their history. By changing the shape of how a container holds its product, companies might be able to reduce the amount of resources needed to make their containers. An example of this would be the redesign that Proctor and Gamble made to its vegetable oil bottles. The company wanted to cut down on the amount of plastic that was being used while also reducing the storage space and weight of the vegetable oil. P&G were able to meet both of these goals simply by changing the geometry of the bottle from a cylindrical shape to one that is rectangular [117] . This change in design used 30 % less plastic reducing the amount of plastic being used by about 2.5 million pounds per year. It also had an impact on reducing the number of shipping containers used for transportation, resulting in a reduction of corrugated containers by about 1.3 million pounds annually. By reimagining the way a container can hold its product, companies can both reduce the amount of resources they use while also cutting down on the cost of both transporting and storing their goods. 106

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8.3.3

Reuse

The last major hurdle companies have when making sustainable packaging for consumable products is the fact that they have not figured out an effective way to reuse the packages that they produce. Throughout the years, companies encountered difficulties to track where their packaging ended up once it was in the customerâ&#x20AC;&#x2122;s hands. By implementing a policy that either allows the customer to return the packaging to the company or to use it multiple times for a consumable product, this will take away the need for companies to keep producing new packaging. An example of a company doing this is the Body Shop. The Body Shop is a beauty store that has committed to sustainability and protecting the planet. A prominent example of their dedication is their refill policy of their bottles [133] . Customers are able to buy a refill bottle on the beauty products they buy such as shampoo or lotion. Once they need more of their product, customers can bring their bottles in to get a refill for a 10 % discount. By adopting policies like the Body Shop, companies can not only save money on packaging but can also enhance their overall image by showing an effort to be sustainable.

8.3.4

Customer Focus

At the end of the day, packaging for consumable items comes down to how customers interact with it. The packaging must exhibit a good user interface with the customer and show that it can provide its desired function; otherwise the customer will not buy the product no matter how sustainable it is [114] . A good compromise to have would be to set a marketing campaign that either changes the focus to the product rather than with the way that it is packaged or to educate the customers on how its packaging will be sustainable. A customer that is either focused on the appeal of the product itself or knowledgeable about how sustainable the packaging really is will make these guidelines for more sustainable packaging much easier to implement.

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Chapter 9 Waste Management A key issue in engineering sustainability is the issue of waste management. Waste management includes the management monitoring, and disposal of waste materials. There are many methods of disposal including incineration, landfill dumping, energy recovery, and recycling. Considering waste management and sustainabilty the use of landfills and incineration needs to be reduced while recycling should be sought after. How material is disposed is only the end of the tunnel with the manufacture or construction of products producing waste, the transportation of products as well as their waste, and any other wastes produced due to the production of the product.The key issues addressed in this chapter on waste management are the waste management issues revolving around office and human sustainability, end of life sustainability issues, bulk waste management, and finally a look at the big picture of waste management. Reducing waste in these areas will greatly increase the sustainability of engineering design, and lead to a cleaner world.

Office and Human Sustainability Minimizing the environmental impact of post-production materials requires management of the products that a company might manufacture, and all the products and materials that are used to create the end product. This can range from day-to-day paper products used by your employees, to food left over in the office kitchen. Here we give guidelines for the proper disposal of the following types of waste: • • • • •

Paper Electronic Chemical Medical Foodstuffs

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Figure 9.1: Fujitsu ScanSnap scanner [136]

9.1.1

Paper Management

The easiest way to minimize the use of paper in the office is to utilize digital information sharing as much as possible. It is estimated that 95 % of business information is still stored on paper [134] . This method of data storage takes up an absurd amount of space in offices (space that is heated and cooled and could be used for something more productive) and is relatively time consuming to access and organize. Inputting data and information stored on paper into an electronic system will prevent the further use of paper products. Although converting to digital will increase electricity usage, especially if data storage is an integral part of what the company does, it will reduce the amount of energy and water used to make paper. Paper manufacturing is the 3rd largest user of fossil fuels worldwide and recycling paper uses 60 % less energy than manufacturing virgin timber [135] . Invest in a scanning system to convert and get rid of any hard copies you have. The type and cost of the scanner(s) will depend on the amount of paper you need to convert. The average four drawer file cabinet holds about 10,000 to 12,000 papers. The amount of digital storage needed for one paper varies with content but averages around 50 kB. This means that an entire file cabinet can fit on less than one GB of space. A one TB external hard drive can be purchased for about $100.00. If the total paper volume is less than 5 file cabinets, converting the data in-house is feasible. Depending on budget, the type of scanner one may invest in has the capacity to minimize the total time and effort expended in this activity. These can range from the Fujitsu ScanSnap (Figure 9.1) to the 25 page per minute Epson WorkForce (Figure 9.2). For more than 5 file cabinets of paper files, consider outsourcing the task. Obviously, once the paper is converted to a digital format, it can be recycled! Going paperless offers other advantages as well, such as the ease of accessing, organizing 111

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Figure 9.2: Epson WorkForce scanner [136]

and archiving data and information. If all the data is stored on one properly secured network, any employee with access to the network is just a few clicks away. After conversion, continually minimize paper use by setting rations or quotas on printing and strict budgets for purchasing paper materials. In the best case scenario, paper should not be used by a company at all. File cabinets should not be purchase and paper should not be purchased. Presentations that involve reports or brochures should use digital versions only and can be presented on tablet computers.

9.1.2

Electronic, Medical, and Chemical Waste

Disposal of e-scrap, medical items and chemical waste can be a health hazard and should be done with extreme care. In this case, recycling is the key objective. Electronic waste includes old computers, office appliances, entertainment devices, mobile phones, and any other electronic product that is no longer usable. All unusable electronics should be sorted and packaged appropriately and sent to reuse/refurbish centers. EcoSquid.com is a useful tool to search for a local facility. Most product manufacturers also offer take-back programs. The Institute of Scrap Recycling Industries (ISRI) offers training which provides Electronics Recycler Certification. Medical waste is any solid waste generated in the diagnosis, treatment or immunization of human beings including blood-soaked bandages, culture dishes, used surgical gloves, used surgical instruments and used needles. For proper disposal, secure drop boxes should be located on every floor of any building. Companies within the medical industry are advised to supply more drop boxes. Medical waste is usually incinerated, but if more than 75 % of the medical waste is hardware, it should be properly segregated and sent for sterilization 112

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Figure 9.3: Recycling computers [137]

and recycling. Chemical waste is very similar. If a company deals significantly with high volumes of chemical waste, designate a Waste Manager who will be responsible for making sure all laws and regulations are followed. If a company deals only moderately with chemical waste, segregate it on site into properly labeled carboys and hire a specialist contractor for disposal, and to ensure safety, health and legislative requirements are met. Segregation should mainly include hazardous (ignitable, corrosive, reactive or toxic) vs. non hazardous materials, and should also include recyclable vs. non recyclable materials. Disposal cost is based on volume, so make sure containers are as full as possible and are sealed properly. Also, containers should not react with the stored waste (e.g. do not put hydrofluoric acid in glass) [138] .

9.1.3

Food Waste

Everyday food waste (food that is discarded uneaten) may seem like a trivial issue, but Americans waste more than 40 % of the food we produce [139] . This contributes to rising prices in foodstuffs and adds to the number of people without enough to eat. Although biodegradable, food should not just be thrown away. If a company is large enough to house its own cafeteria, develop a partnership with a local farm or fertilizing company to collect the food waste from the kitchen. Leftovers (not waste) can be donated to local homeless shelters and/or soup kitchens. If a company does not run a cafeteria, but has an employee kitchen of some sort, take a few simple measures to become more sustainable. Have a garbage disposal installed in every kitchen sink (food waste will be ground up and treated like regular wastewaterâ&#x20AC;&#x201C;turned into biosolids and fertilizer) and if kitchen appliances are purchased be sure that they are EnergyStar appliances.

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Figure 9.4: EnergyStar logo [140]

In summary: • • • •

convert all information from paper to digital, and recycle the materials, cease all purchases of paper, paper products, and file cabinets, become a Certified Electronics Recycler, provide an appropriate number of secure disposal containers for medical waste to ensure separation of materials heading for incineration and recyclable materials, • separate, label and store chemical waste in appropriate, sealed containers and recycle as much as possible, • consume all food produced, and • install garbage disposals and use only EnergyStar kitchen appliances.

Post Product Life Sustainability 9.2.1

Recycling at End of Life

For products that do not have an infinite life, designers must consider the fate of their products after they are no longer wanted by the consumer. Sustainable designs consider not only the manufacturing processes’ impacts on the environment, but also the degree to which products interact with the environment after being discarded. Few consumer products are as simple to recycle as aluminum cans and newspapers. Many are comprised of multiple materials, parts, and systems that cannot be easily separated for disposal. The pieces, 114

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Table 9.1: List of recyclable materials adapted from EPA [141] Recyclable Material Aluminum Batteries Consumer Electronics

Examples Beverage cans, packaging, automobile parts Dry-cell batteries, wet-cell batteries Computers, televisions, cellular phones

Glasses Oil

Food containers Engine oils, synthetic oils, cooking oil

Plastics Steel

PET, HDPE, PVC Food containers, automobile parts

Textiles

Fleece, flannel, cotton, wool

however, are often made from materials that can be reused and recycled. Designers must consider the effort required to disassemble their products for recycling. To address endof-life issues, designs may reduce the number of different materials going into the product, minimizing the effort required by the user to separate.

9.2.2

Recycling Materials

Until more options become available for selecting materials that decompose safely in landfills, designers are encouraged to utilize recyclable materials. The Environmental Protection Agency offers a list of non-hazardous materials currently collected for recycling in the United States. [141] By making an effort to use as many of these materials as possible into the design, the product may be recycled at the end of its life.

9.2.3

Non-toxic Materials

Sustainable consumers are unlikely to purchase products that are made from materials that will leak toxins into the environment when disposed. Ideally, designers would refrain from including toxic materials in their manufacturing processes. However, if they must be used, care should be taken to properly instruct consumers on how to safely dispose of their product. Here are some useful ways to dispose of these hazardous materials effectively. [142]

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CHAPTER 9. WASTE MANAGEMENT • • • • •

Use and reuse as much of the material as possible, making it last for as long as possible Do not mix hazardous wastes or dispose of them together in a single container Solidify liquid wastes using any type of absorbent material Do not bury containers of remaining chemicals Know what can and cannot be poured down a drain and placed in regularly collected garbage

9.2.4

Frequently Discarded Components

If the design incorporates components that are intended to last for a significantly shorter time than the rest of the entire product, it is crucial that these discarded components be made of recyclable or biodegradable materials. For example, a trash can is intended to last for years, but the liners are only good for as long as it takes to fill the can with trash. These plastic bags that end up in landfills will never have the opportunity to be recycled, so they are truly destined for “one-time” use. If it is not possible to use recyclable materials when creating these components, then designs must eliminate discarded parts, focusing on keeping all pieces of the product with the user during the entire life of the product. A successful example of this is seen in printer ink cartridges that can be easily refilled by the user.

Bulk Waste Management When speaking about sustainability in the context of waste management, evaluating ways that sustainability can be achieved in the management of bulk waste is crucial. Bulk waste typically describes forms of waste that are too large to be handled by regular waste collection methods. In industry, this waste often comes from manufacturing plants as well as sites of construction or demolition. In the analysis of bulk waste management, manufacturing waste management is considered individually and waste management for construction and demolition are considered as a group.

9.3.1

Manufacturing Waste Management

Manufacturing processes often lead to the production of large amounts of waste that cannot often be handled by conventional methods. Manufacturing bulk waste often includes outdated manufacturing equipment that has been updated, heavy tools, appliances and large amounts of scrap materials [143] . Manufacturing bulk waste also often includes a high volume of chemical waste, created as a bi-product of manufacturing processes. These volumes of chemical waste (often synthetic chemicals, solvents or metals) need to be properly processed and transported in order not to harm the environment [144] . Thus, sustainable waste processing and transportation methods should be used for manufacturing bulk waste. In the 116

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Table 9.2: Sustainable Benefits of Waste Processing Methods [145] Process

Sustainable Benefits

Compacting Shredding

• Waste volume reduction leads to an increased amount of waste per transportation cycle • Volume reduction decreases transportation related emissions per volume of waste

Sterilization

• Cleanses waste of potentially harmful bacteria • Allows for previously contaminated waste to be compacted or shredded and disposed of without harm

vein of waste processing methods, typical waste processing for metals and solid industrial wastes include compacting, shredding and sterilizing, Table 9.2 documents the benefits of compacting, shredding and sterilizing in the context of sustainability. For chemical waste, processing methods differ in that waste often cannot be compacted or sterilized; however, the containers that held this waste can often be sterilized and disposed of in the aforementioned ways. For the processing of chemical waste, the biggest challenge to sustainability is identifying toxic chemical waste and transporting it safely to previously identified areas for toxic waste disposal. Typical waste transportation methods include transportation by truck, rail and barge. Each of these methods involves significant emissions that are harmful not only to humans but also to entire ecosystems. By way of comparison between these methods, carbon dioxide emissions per million ton-miles (emissions generated by shipping one ton of cargo one million miles) for an inland barge are 19.3 tons, while the average rail car produces 26.9 tons and the average freight truck produces 71.6 tons [146] . With these figures in mind, a sustainable transportation strategy should focus on the use of inland barges and rail transportation when possible as the emissions from these methods represent nearly 27% and 37% of freight truck emissions, respectively. However, barge and rail transportation are highly location specific and do not offer the flexibility of traditional freight trucking. In the event that trucking is the only option for waste transportation, the following guidelines should be followed: 1. Consolidation: Manufacturing facilities should seek to maximize the waste loaded into each freight truck to limit the number of vehicles necessary for complete waste transportation. 2. Elimination: Industrial facilities should also seek to eliminate waste materials by considering the reuse of materials when possible. Scrap metals represent an ideal material capable of being reused instead of shipped away as waste.

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CHAPTER 9. WASTE MANAGEMENT 3. Optimization: The use of freight trucks that are optimized for fuel economy, such as those that have minimized aerodynamic drag, can increase fuel efficiency by 3.6% and decrease the carbon dioxide emissions of a single truck by .76 metric tons per year [147] . Strategies such as this, as well as developing and utilizing hybrid freighter options, are encouraged to limit emissions of freight trucks.

9.3.2

Construction and Demolition Waste Management

Construction and Demolition processes can also generate large amounts of bulk waste. This waste typically takes the form of unused or demolished structural material- steel, aluminum, concrete and wood. With such structural components, the same rationale applies as was considered for manufacturing bulk waste–the waste should be processed in ways to minimize its volume and toxicity, and transportation methods should be employed that reduce carbon emissions. One major difference, though, between construction and demolition sites as opposed to a manufacturing plant, that must be factored into waste management considerations is location. Manufacturing plants often have the benefit of a fixed location over a long period of time–this allows for waste processing operations to occur onsite. Construction and demolition sites are often at one site only temporarily and with limited space for large waste processing machinery. When possible, waste processing machinery should be located at the construction site; however, when this is not cost effective or reasonable to achieve, transportation of this waste should be optimized using the method described above with emphasis on the elimination of waste through reuse of materials in construction areas. Ultimately, the management of bulk waste boils down to a management of the waste density and toxicity– compacting the greatest mass of waste into the smallest, cleanest volume. Managing the size of the waste allows for the efficient use of transportation methods, whose environmental impact can be mitigated by increasing fuel efficiency or hybridization. Managing the waste toxicity allows for the waste to be disposed of in ways that do not adversely affect humans, ecosystems or the environment at large.

Big Picture 9.4.1

Waste as a Source of Energy

Incineration Mechanical engineers should be knowledgeable in the energy aspect of waste in products. Waste can be used as a source of energy, either directly as fuel or as electricity. Currently the most common waste-to-energy process is in incineration, shown in Figure 1.5. Incinerators effectively reduce the amount of waste and can reduce the volume of waste by up to 96%. Incinerators work by first burning the garbage and then using that heat as boilers to power steam generators. These generators ultimately create electricity for use. Incinerators, however, are somewhat inefficient in converting the waste to electricity, having efficiencies 118

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Figure 9.5: Diagram of incineration [149]

between 14% and 18%. The process of incineration also comes at an environmental cost. Many pollutants are released into the atmosphere as a result of the burned waste. The most severe consequence is the formation of acid rain, which damages forests and other natural habitats. There have been strides in reducing acid rain as the smokestacks are now being lined with lime scrubbers, an acid neutralizer. [148] Gasification There are other methods of using waste as a source of energy. One of those methods is gasification, which is shown in Figure 1.6. This is a process that takes biodegradable materials and converts them into a â&#x20AC;&#x153;producer gasâ&#x20AC;? which can be used as a fuel. Gasification includes conversion of the organic waste into electricity. Gasification is also more efficient and less expensive than incineration and is a very feasible solution for a source of energy. Gasification is more environmentally friendly as it releases the ash from heavy metals in a chemically stable form, unlike incineration where it is released through the air. Engineers should utilize organic materials in design and manufacturing to allow for the use of more efficient renewable sources of energy. Because there are methods of using organic waste to create energy which are much more efficient and less harmful to the environment, engineers should consider the choice of materials used in production. [151]

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Figure 9.6: Diagram of Gasification [150]

9.4.2

Waste Generation Monitoring Methods

Frequent Monitoring of Products in Manufacturing Manufacturing plants inherently create waste because they do not monitor their products in a timely manner. Manufacturers can minimize the number of defective products that become garbage by just monitoring the status of the product in assembly and manufacturing. A simple solution would be to have an inspector check the products more frequently. [152] Optimizing Resources Another method in monitoring waste generation is optimizing resources in manufacturing. Manufacturers should aim to reduce the amount of waste in raw materials. This will not only be cost effective for the manufacturing company, but also reduce the amount of materials consumed. If raw material is left over, try to utilize the scraps for other uses so that the raw materials wasted are minimized. [152] Over-Design for Durability There can be better waste monitoring in the design process as well. To reduce the amount of waste on the customerâ&#x20AC;&#x2122;s end, the engineer can over-design the product to ensure durability so that the product lasts as long as intended or longer. This will reduce the amount of products that will be thrown away because of durability issues. Recyclable Materials for Packaging The designer should also think about the materials used in packaging. Because packaging will most likely be thrown away by the consumer, the least amount of material should be used to reduce the waste created. The designer should also consider using only recyclable materials to further reduce the waste. Materials such as Styrofoam, plastic films and other non-recyclable items should be avoided. Sustainable Materials 120

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CHAPTER 9. WASTE MANAGEMENT The engineer can also search for different, more sustainable resources or materials that can be used instead of the current choice. Designers now have the notion that cheaper is better and because of this, there is no consideration in what happens to the product after it leaves the factory. Designers should consider easy disassembly of products to reduce and transform waste into recycling. If the product is easily disassembled, there will be a higher chance that the product will be properly recycled at the end of its life.

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Chapter 10 Green Label Benchmarks and Evaluation The sustainability of products will be judged against the Green Label Benchmark. In order to obtain the Green Label for a product, the product must meet rigorous criteria. The following five sections outline the standards that must be met by products that wish to obtain the Green Label.

Information Companies must Provide 10.1.1

Introduction

It is important for companies to provide consumers with the environmental information of what goes into each product. Every consumer deserves to know what the environmental impact of the products that they are buying. Therefore in order to be considered a Green Label product [153] , companies must provide an environmental informational label for every product similar to a nutritional label on food. Companies are then forced to publically show the environmental effects of their products and since conscientous consumers do not want to buy products that are harmful to the environment this would drive companies to improve these effects to increase the marketability of their product. In addition to this, it would be easy for a regulating committee to look at the label and determine if the product met the Green Label standards or not. 124

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CHAPTER 10. GREEN LABEL BENCHMARKS AND EVALUATION The five important categories that must be included on this environmental label would be: 1. 2. 3. 4. 5.

the the the the the

10.1.2

Energy Used in the production of each product, Carbon Footprint of each product, Percentage of Recyclable Material in each product, List of Materials used to make each product, and Waste Created by the production of each product.

Energy Used in Production of Each Product

One of the primary pieces of information that should be included on this product info label is the amount of energy that was used in the production of the product. The energy needed to create and distribute the product would be measured in joules. It is possible for a product to use all of the right materials to make it a Green Label product, but if there is excess energy being used in production then the product relinquishes its Green Label. It is also important to indicate whether the energy consumption is coming from production or the transportation and distribution of goods, as it would indicate an area that the company could improve and become more efficent. In addition to this, where the energy is coming from should be shown by breaking down the energy used into subsections (i.e. electricity, oil, coal, gas, solar and wind). This will give an inclination of how hard the company is trying to use renewable sources of energy instead of using up fossil fuels which is detrimental to the environment.

10.1.3

Carbon Footprint Left By the Product

An important effect of a product that often goes unnoticed is the carbon footprint that it leaves behind. The production and transportation of a product often leads to large carbon emissions that are harmful to the atmosphere, yet this is not recognized by the common user of the product. Therefore it will be required to indicate on the label the carbon dioxide and methane emissions that are produced by the formation and distribution of a product [154] . By including this on the label the consumer will be informed of the carbon footprint that they are contributing to the planet by purchasing this product, and it will motivate the manufacturers to reduce their emissions to meet the Green Label standards.

10.1.4

Percentage of Recyclable Content

Another part of the label that would be required would be data showing percentage of recyclable material. Companies would have to break down the materials into categories of recyclable glass, plastics, paper, metals and then the remaining unrecyclable products. By doing this the consumer would be able to see exactly how environmentally friendly the product is, and it would show the extent the company went to create a product that could 125

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CHAPTER 10. GREEN LABEL BENCHMARKS AND EVALUATION be broken down and completely recycled. It should be the goal of all products to have as small a percentage of unrecyclable content as possible.

10.1.5

List of Materials Used

One of the required aspects of the information label would be the list of materials used Table 10.1: Product Label Template to make up the product and in production. This would be similar to the ingredients that Environmental Label go into a food product on a food label. By Energy Used: (Joules) requiring this, it would hold companies responsible to fully disclose what is in each Transportation: product and what chemicals were used in the Production: production of the product. Often the mateEnergy Sources:(%) rials that are used in production go unknown Electricity: to the consumer and they believe they are buying a green product when they really are Gas: not. Forcing companies to put this inforOil: mation on the box would cause them to be Coal: truthful about their products and influence them to choose materials and chemicals that Solar: are more environmentally friendly. Wind: Other:

10.1.6 Waste Created By Each Product

Carbon Footprint: (Tonnes) Methane:

Companies should also indicate the waste that is created in the production of each product. Whenever products are made there is waste that is created and often discarded into a landfill, such as raw materials and toxins. It is important for companies to take ownership to the waste that they are creating, and this section of the environmental label would do that. A product may advertise itself as being green because of the materials that it is made out of, and the amount of energy that is used in production, but if it is creating harmful waste then it cannot be considered green and including this information in the environmental label on the box would do this.

Carbon Dioxide: Recyclable Materials: (%) Glass: Plastic: Paper: Metal: Non-Recyclables: Materials: Waste:(Tonnes)

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10.1.7

Conclusion

Based on the information that would be most beneficial to the consumer in determining whether a product is green, the design of the environmental label can be found in Table 10.1. By completing this table and putting it on their products, companies would be providing consumers with information showing how environmentally friendly their product it. In addition to this it would be easy for government regulators to recognize which products are harmful to the environment since companies would be required to disclose all the information on their label.

Product Life Requirements 10.2.1

Product Life Considerations

Certification of your product to obtain the “Green Label” includes an assessment of your products life cycle and services and the environmental impact. Reducing the environmental impact requires knowledge and wisdom about how the consumer’s use the products as well as where the products came from and where they will go until the end of their lifespan. Several factors influence the environmental impact of the product; the energy used to manufacture, distribute, and use a product; the product’s raw materials and contents need to be considered; the emission levels and toxins which are produced during the manufacturing process; and the product’s end of life recyclability.

10.2.2

Setting the Standard

There is no set standard to which all products’ lifespan must meet. Several products are broken down into categories and classes which are then given standards to meet. However, the Green Seal is a non-profit organization, which has developed lifecycle-based sustainability standards for products, services and companies. They have been reviewed by ISO, ANSI, and GENICES and found to have met credible standards and guidelines in regards to certification of product life cycle. Green Seal standards for a product’s lifespan have several requirements which each product must meet on an individual or class basis. In order for a product to obtain a “Green Label” it is important to consider the following product requirements [155] : • Scope • Performance Requirements – Specific Industry Compliances – Energy Star, etc • Health and Environmental Requirements • Manufacturing Requirements • End of Life Requirements 127

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CHAPTER 10. GREEN LABEL BENCHMARKS AND EVALUATION – Waste Material vs. Recyclability • Packaging Requirements • Labeling Requirements These are the necessary product lifespan requirements which a “Green Label” product must adhere to in order to achieve certification. The following examples introduce just how specific the lifespan requirements can be for each individual product.

Examples of Selected Lifespan Requirements 10.3.1

Example: Compact Fluorescent Lamp (CFL)

Compact fluorescent lamps are certified with a “Green Label” by meeting the standards set by the Energy Star CFL program. The average minimum lamp life must be 10,000 hours at 3 hours per day. Another specific lifespan requirement is the interim life test. At 40 % of life the product must not fail more than three times to qualify.

Table 10.2: Qualified CFL Warranty and Lifetime Statements Chart from Energy Star

10.3.2

ENERGY STAR Qualified CFL Rated Lifetime

Number of Years Claim (Based on minimum use of 3 hours/day)

6,000 hours

5 years

8,000 hours

7 years

10,000 hours

9 years

12,000 hours

11 years

15,000 hours

13 years

Lifetime Performance Standard Examples

One example of a standard set by a general class of products are those set for paints and coatings. The Green Seal general standard states that there must be no signs of blistering, chalking, cracking, flaking, or loss of adhesion with a max change of 10 gloss level units after 500 hours using a standard light bulb. One example of a standard which is individualized for specific product performance is those set for stains and finishes. Table 10.3 depicts all of the categories with specific product life requirements which must be met by the product in order to obtain certification.

128

Stains & Finishes

129

Stains

Blush Resistant

Adhesion

Blister Resistance

Chemical Resistance

Salt Spray Resistance

Reversibility

Wear Resistant

UV Resistant

X X

Exterior Finishes Ext. Metal Lacquers

Pencil Hardness

Sealers Ext. Forming Stains

Water Resistant

Interior Finishes

Int. Metal Lacquers

X X

CHAPTER 10. GREEN LABEL BENCHMARKS AND EVALUATION

Table 10.3: Stains and finishes lifespan requirements from Green Seal

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CHAPTER 10. GREEN LABEL BENCHMARKS AND EVALUATION

Maximum Energy Consumption during Production Energy consumption is one of the largest problems facing manufacturers in todayâ&#x20AC;&#x2122;s world. People around the globe are consuming more goods and services than ever before, which means that companyâ&#x20AC;&#x2122;s production rates are soaring to unbelievable heights. The primary areas of consumption fall under petroleum, natural gas, coal, renewable energy, and nuclear electric power. According to the 2010 Annual Energy Review, the total energy consumption in the United States has increased from about 33 quadrillion Btu in 1950 to over 90 quadrillion Btu in 2010 [156] . This means that U.S. energy consumption nearly tripled over a 60 year span and this rate will not be sustainable for the future. It is imperative that manufacturers and producers drastically cut the amount of energy they consume each year. In order to produce Green Label products in the near future, it is essential that maximum energy consumption limits be placed on all production companies. The limitations will be based upon what types of goods or services are being produced and what types of energy and resources are being consumed. This section will explain how these limitations should be created for production.

Figure 10.1: Energy consumption from Annual Energy Review [156]

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10.4.1

Measuring energy consumption

The first step will be measuring the amount of energy that is consumed during production for a specific good or service. The methods used to quantify the consumption must be accurate and consistent with other methods used around the world. A consistent unit of measurement for energy consumption is the British thermal unit (Btu). Wattage, horsepower, and thermal measures can be converted to Btu which makes it an accurate unit of measurement for power consumption during production.

Figure 10.2: End-use sector total consumption and shares from Annual Energy Review [156]

10.4.2

Production

According to the 2010 Annual Energy Review, industrial sectors consume the largest amounts of energy in the United States at 31 % of total energy consumption. Clearly production within the industrial sector is accounting for a significant amount of total energy consumption. Within the industrial sector, the primary sources of energy being consumed are petroleum and natural gas [156] . The total energy consumption for manufacturing in the U.S. during 2006 was over 21.1 quadrillion Btu. This means that nearly 25 % of the United Statesâ&#x20AC;&#x2122; total energy consumption is a result of manufacturing and production. With manufacturing and production being such an integral part of energy consumption, limitations in this area will be of a great benefit to the overall goal of reducing energy consumption.

10.4.3

Implementing limitations

Implementing energy consumption limitations is definitely a complex and dynamic procedure. The problem is quite clear; too much energy is being used for production. However, it is difficult to come up with a straightforward, universal solution to this continuing problem. It would not be practical to set an energy consumption limit that was the same for all 131

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CHAPTER 10. GREEN LABEL BENCHMARKS AND EVALUATION companies. Every manufacturer produces different types of goods. There are two primary variables that will determine how much energy will most likely be consumed for production. These variables are the type of product and the quantity that will be produced. Some products like automobiles are going to require more energy to produce compared to a product like an electric razor. First of all they are on completely different size scales. An automobile consists of thousands of different parts and components and can weigh thousands of pounds while an electric razor may be composed of 60 components and weigh less than half of a pound. Clearly more energy will be consumed in the production of the automobile since it will require more material and more labor. It would not be practical to limit the automotive manufacturer to use the same amount of energy to build the car that is used to produce one razor. In order to make a quantitative comparison, an engineer would need to use a ratio between different products in order to evaluate their energy consumption criteria. For example, one car could be compared to 15,000 electric razors in terms of energy consumption. After a ratio is established, there will be a more clear sense of how to compare energy consumption throughout different production industries. In addition to the type of product, the quantity of production is another important factor in determining an appropriate energy consumption limit. Products that are essential to peoplesâ&#x20AC;&#x2122; everyday lives are usually going to be produced in high quantity due to the high demand. These types of products should definitely be focused on because a small change in production could lead to monumental cutbacks in energy consumption throughout the globe. Engineers must pay attention to detail and discover where inefficiencies are, how they can be eliminated, and ultimately how to increase productivity while minimizing energy consumption.

Emissions Levels During Production There are already a number of major environmental statutes and regulations in place for the majority of business sectors. The United States Environmental Protection Agency (EPA) identifies the following six main air pollutants: Carbon Monoxide (CO), Lead (Pb), Nitrogen Dioxide (NO2 ), Ozone (O3 ), Particulate Matter (PM) and Sulfur Dioxide (SO2 ). In order for products to meet emission level standards to be labelled a Green Product, the production factories must be in the bottom ten percent in amount of emissions for each of the main pollutants.

10.5.1

Carbon Monoxide

Carbon monoxide is a result of the combustion process, so many of the vehicles used in the production process must be wary of this standard. Since carbon monoxide is naturally occurring, the artificial emission of carbon monoxide into the air can have a detrimental affect. In order for products to obtain a Green Label, production must meet the concentration 132

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CHAPTER 10. GREEN LABEL BENCHMARKS AND EVALUATION standard of 1 ppm. This meets the criteria of the bottom ten percent according to data from a 2009 EPA study.

10.5.2

Lead

Though the input of lead into the air is mostly from on-road motor vehicles, there is still a certain input of lead into the air from the production process. In order for products to µg obtain a Green Label, production factories must meet the standard of 0 m 3 of lead. This meets the criteria of the bottom ten percent according to data from a 2009 EPA study.

10.5.3

Ozone

Industrial emissions of oxides of Nitrogen and volatile organic compounds will react in the sunlight to produce “bad” ozone that will harm the atmosphere. This affects how much sunlight hits the Earth’s surface or is trapped in the Earth’s atmosphere. In order for products to obtain a Green Label, production must meet the concentration standard of 0.06 ppm of ozone. This meets the criteria of the bottom ten percent according to data from a 2009 EPA study.

10.5.4

Particulate Matter

Particle matter is a catch-all emission that includes acids, organic chemicals, metals and soil or dust particles. These are fine particles that are emitted during the manufacturing process. In order for products to obtain a Green Label, production factories must meet the standard µg of 28 m 3 of particulate matter. This meets the criteria of the bottom ten percent according to data from a 2009 EPA study.

10.5.5

Nitrogen Dioxide

Nitrogen dioxide forms from the production process (usually in power plants). In order for products to obtain a Green Label, production factories must meet the concentration standard of 0.00435 ppm of nitrogen dioxide. This meets the criteria of the bottom ten percent according to data from a 2009 EPA study.

10.5.6

Sulfur Dioxide

This fossil fuel emission has dramatic effects on the environment, as it is a highly reactive gas. In order for products to obtain a green label, production must meet the concentration standard of 0.00115 ppm of ozone. This meets the criteria of the bottom ten percent according to data from a 2009 EPA study.

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CHAPTER 10. GREEN LABEL BENCHMARKS AND EVALUATION

Green Standards for Sources of Raw Materials Commonly, sustainable design focuses on the side of manufacturing that determines the amount of material, energy, and quality put into a product. Yet, there is another side to green engineering that should be taken into account. The source of the raw materials used in a product should be considered when utilizing green labeling. Raw materials are the basic building blocks of all products such as wood and crude oil. These materials come directly from the environment, and are present in a limited supply. There are many areas of the world that are suffering because of the exploitation of their resources by industry. Being aware of where raw materials are coming from to ensure that the entire manufacturing process has an focus on sustainability.

10.6.1

Ecosystems in Danger

A large source of raw materials are the forests around the world. Each forest is an ecosystem in itself and contains a wealth of natural diversity. Forests cover about 9.4 % of the Earthâ&#x20AC;&#x2122;s surface and are estimated to hold about two-thirds of the land plant and animal species [157] . A forest can be threatened because it is a direct source of wood for many uses. But forests are threatened indirectly by mining, oil drilling, and the development of agriculture. The following list goes into the specific forests of the world that are being threatened by various influences. These areas must be taken into special consideration when looking for sources of raw materials for manufacturing. In Figure 10.3, a map identifies these main forest areas that should be protected from extreme exploitation.

Figure 10.3: Global view of the worldâ&#x20AC;&#x2122;s most endangered forests [157] 134

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CHAPTER 10. GREEN LABEL BENCHMARKS AND EVALUATION Below is a list of the largest forests of the world that are being the most threatened according to the London newspaper, The Guardian: 1. 2. 3. 4. 5. 6. 7. 8.

North American Forest Central American Forest Amazon Forest South American Forest Gola Forest Congo Forest Russian Forest Southeast Asian Forest

The most common threats to these forests vary according to region but include agriculture, logging, mining, plantations, and power generation. Each area represents a huge number of species that are in danger. The forests offer not only species diversity, but also a significant percentage of the world’s oxygen. In addition, these forests are important aspects of the economies of these countries. When destroyed, the areas will be left with nothing and the effects would be detrimental.

10.6.2

Standards of Protection

Certain governmental policies have individual regulations for a state or country that protect their natural areas from exploitation. In terms of engineering companies and industries, there are private councils and societies that have their own standards to protect the environment. When a company follows all the desired standards, they are given a unique certification. One such council that is extremely highly utilized throughout the engineering field is the Forest Stewardship Council (FSC). The FSC’s standards are focused on the protection of forests throughout the world. The FSC has a set of main principles that must be met in order for certification to be achieved. Though these principles are developed specifically by FSC, they are general concepts that are vital to achieving protection of the sources of any raw materials. Any company or engineer can view these principles to promote their consideration of the protection of natural resources. The following criteria are adapted from FSC International Standard: FSC Principles and Criteria for Forest Stewardship [158] : • • • •

Following of laws and international treaties. Demonstrated and uncontested, clearly defined, long-term land tenure use rights. Ensuring indigenous people’s rights. Ensuring long term social and economic well being of worker’s rights in accordance with the International Labour Organization. • Equitable use and sharing of benefits from forest. • Reduction of environmental impact of logging and maintenance of function and integrity of the forest. 135

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CHAPTER 10. GREEN LABEL BENCHMARKS AND EVALUATION • Continually updated management plan, frequently assessing the conditions of the forest. • Maintenance of environmental and social values that are of critical importance. • Plantations must reduce pressure on the forests and contribute to their conservation. These items provide a specific set of regulations that be met in order for a company to be considered certified. The main issues that threaten natural resources are addressed in these points. These factors include the indigenous people, the local laws, and the overall environmental effects of the process. The regulations promote a conservative approach to utilizing the resources found in these forests, but can be applied to essentially any area where natural resources are being removed from. Other areas such as deserts, mountains, or oceans where resources such as crude oil, soil, or any other type of natural product are being removed deserve the same standards [159] . Green labels should not be considered viable unless there is explicit reference to standards such as these. Green labels need to account for where raw materials come from, and standards like these are the way to ensure the protection of our environment. Ultimately, green labeling should include a section devoted to the sustainable treatment of raw material sources. This is an aspect of sustainable design that is sometimes overlooked. But, the conservation of our world’s natural resources is essential not only for current green design and labeling, but for the future of manufacturing. Without protecting our natural resources now, we will not be able to continue to produce the goods needed in the future.

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BIBLIOGRAPHY [44] Association of Postconsumer Plastic Recyclers. The Association of Postconsumer Plastic Recyclers Design for Recyclability Program. http://http://www. plasticsrecycling.org/images/stories/doc/dfr_2011_may.pdf, 2011. Accessed: 25 October 2011. [45] Practical Action Technology Challenging Poverty. Recycling Plastics. http:// www.itdg.org/docs/technical_information_service/recycling_plastics.pdf, 2011. Accessed: 25 October 2011. [46] Plastics and Sustainability. plastics-sustainability.aspx, 2010. are sustainable.

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