LESSON 13 TEXTILE TESTING: AN OVERVIEW STRUCTURE 13.0
OBJECTIVES
13.1
INTRODUCTION
13.2
WHAT IS QUALITY?
13.3
DIMENSIONS OF QUALITY 13.3.1 13.3.2 13.3.3
THE OVER-DIMENSIONED QUALITY THE UNDER-DIMENSIONED QUALITY THE DIMENSIONED QUALITY
13.4
WHY IS QUALITY IMPORTANT?
13.5
APPROACHES TO MANAGEMENT OF QUALITY 13.5.1 13.5.2 13.5.3
STATISTICAL QUALITY CONTROL (SQC) TOTAL QUALITY CONTROL (TQC) TOTAL QUALITY MANAGEMENT (TQM)
13.6
ROLE OF STANDARDS IN QUALITY CONTROL
13.7
ASSIGNMENTS 13.7.1 13.7.2
CLASS ASSIGNMENTS HOME ASSIGNMENTS
13.8
SUMMING UP
13.9
POSSIBLE ANSWERS TO SELF-CHECK QUESTIONS
13.10 TERMINAL QUESTIONS 13.11 REFERENCES 13.12 SUGGESTED FURTHER READING 13.13 GLOSSARY
13. TEXTILE TESTING: AN OVERVIEW To those engaged in the production, distribution and consumption of textiles and textile products, testing can be a valuable aid as it helps in the selection of raw materials, process control, process development, product design, etc. This being the first lesson of the unit on ‘Textile Testing’, it would be appropriate to give first an overview on quality, quality control, standards etc. In the two subsequent lessons, the actual tests performed on textile fibres, yarns, fabrics, etc. and the instruments and equipment used fo making these tests, will be described.
13.0 Objectives After going through this lesson, you will be able to understand •
The meaning of the word quality.
•
The various dimensions of ‘Quality’.
•
Why quality is important?
•
The various approaches to the management of quality-including statistical quality control, total quality control and total quality management.
•
The role of standards in quality control.
13.1 Introduction The common perception in the mind of people that testing is done to assess quality is still substantially correct though the exact dimensions of quality may not be clearly understood by them. There is ample evidence that quality has been with us since the dawn of civilization as archeological sites like Mohenjodaro clearly suggest. However the concept of quality, as we understand it today, seems to have emerged since about the Second World War. Quality of the product has to be good to satisfy customer expectations and it ensures success and survival of the company, particularly in a globalised economy. The concept of quality, which is measured by simple inspection of finished goods, has undergone a quantum change and now encompasses a much wider framework, viz the whole organization, which is treated as a system with the entire focus being on the customer and his needs. According to this extended concept, quality must be planned and not tested. Quality considerations are important not only during production but also in the designing stage. A good example of this is given by Pradip V. Mehta in reference 1 (in section 13.11) for a garment manufacturing unit. The factors that count for such a unit are – selection of fabrics, seam and stitch types, proper pattern grading for good fit for the entire size range, appropriate fabric grain direction, selection of buttons, zipper, etc. One cannot expect quality garments where buttons cannot withstand laundering, dry cleaning,
pressing, etc. One cannot produce a quality garment if the fabric it is made from shrinks excessively upon laundering and/or is not colourfast. Chain stitch may be better than lock stitch where some extensibility of the seam is desired.
Self-check Questions 1. Fill in the blanks i) According to this extended concept, quality must be ___________.
________ and not
ii) For a quality garment, the fabrics must not __________ and be ________________.
13.2 What is Quality? The question may seem a bit superfluous because most people think that the answer of this question is self-evident and that they know what quality is. However if they are questioned further, it becomes obvious that while they can perceive or feel what quality is, they are not able to quantify this rather complex parameter which has many dimensions. The International Standards Organization (ISO) defines quality as follows, “Quality in the totality of features and characteristics of a product or service that bear on its ability to satisfy the stated or implicit needs”. Thus factors like durability, reliability, serviceability are different dimensions of quality. Garvin ( Ref.2 in section 13.11) gave eight dimensions of Quality , three of which are implied in the definition of ISO. The other five are : performance (how effective it is), features (supplementary plus points), conformance (how it meets standards), aesthetics and perceived quality (as perceived by the customers on the basis of say advertisements) Quality is also defined in terms of “fitness for use” (Reference3 in section 13.11), a concept which can be applied to garments which must: •
Be free from defects such as stains, material (fabric) defects, open seams, misaligned buttons etc.
•
Fit properly for the labeled size
•
Perform satisfactorily in normal use
13.3 Dimensions of Quality Different degrees of quality levels are known. If they are brought together in a common standard scheme, the following three clearly defined classifications emerge (references 4 and 5 in section 13.11). 13.3.1 The Over-dimensioned Quality Today this is still the most common type of quality found in the marketplace, by far also the most uneconomical. Fig.13.1 visualizes such an over-dimensioned quality.
Fig.13.1 Over dimensioned yarn Quality (Taken from Ref. 4)
Fig.13.2 Discrepancy between requirement and quality level (Taken from Reference 4)
The actual quality level i.e. the quality of the yarn under reference, is much above the required level. This span between the requirement and the measured actual quality results in considerable costs for the producer and the customer as is evident from Fig. 13.2. This arises because often the exact knowledge of the requirements for the yarn is missing, frequently as a result of the non-existence of product engineering. 13.3.2 The Under-dimensioned Quality Fig.13.3 shows that the under-dimensioned quality is not a result of insufficient average quality levels, but of the exceptions, which happen with a certain frequency. These exceptions further render a yarn useless for certain applications due to the high loss of efficiency of downstream production equipment.
In considering over-dimensioned and under-dimensioned quality, we have considered yarn breaking force as the quality characteristic. For a yarn such quality characteristics would be much larger and in reference 4 of section 13.11, twelve such characteristics have been considered like evenness, thin places, thick places, Neps, Tenacity, percentage elongation, count CV percentage, elongation CV percentage, etc. Out of these nine characteristics were above the requirement level and three below. This could be the result of incorrectly selected raw material or a yarn production process that was not optimal. 13.3.3 The Dimensioned Quality This quality level can also be described as the optimum or the economical quality i.e. all requirements are fulfilled not more but not less either.
Self-check Questions 2. What are the eight dimensions of quality? 3. What is the meaning of over-dimensioned Quality? 4. What is meant by under-dimensioned quality?
13.4 Why is Quality Important? The answer to this question may appear to be self-evident but there are some aspects that may not be so apparent. Some of these will be highlighted here. Studies have shown that product quality shows a good correlation with Return on Investment and that firms producing goods of superior quality have greater market share. The six benefits of quality that came out of another study are: • • • • • •
Greater market share Higher earnings Loyal customers Higher growth-rate Premium price Higher motivated employees.
Activity 1.
Can you think of four good reasons why return on investment is higher if the quality of goods is high?
13.5 Approaches to Management of Quality In the earlier discussion, we tried to understand the meaning of quality and its dimensions. We also looked into the question as to why quality is important. The next area of interest is obviously to go into the question of managing quality. The term ‘Quality Control’ was widely used at one time and was considered to be within the domain of the worker or the foreman. As per the age old ‘craftsman approach’, only the end-product was subject to tests and the responsibility for a poor product was that of the worker or his supervisor. In the 1930’s, the idea was mooted that a given result is produced by a set of conditions or a process not by a specific individual. This led to some drastic change in thinking and a new approach to quality management. 13.5.1 Statistical Quality Control (SQC) The need to study the characteristics of a process became clear when the old techniques of assessing quality were found to be inadequate. The obvious choice was to use numbers or data, i.e. statistics for this purpose. This gave rise to the concept of statistical quality control or SQC. When the whole process was studied with the aim of controlling quality of the product, spectacular reduction in losses was reported by many companies in the US. A carpet manufacturing company in U.S.A. applied this approach to its carding department in 1949 and reported a saving of around two million US dollars in the very first year of the operation of the quality control programme. In spite of the success of SQC programme, there was a strong feeling that the base for quality management needed still more widening as other wings of the organization rather than process alone, also needed to be taken into account. The concept of total quality control came up as a result 13.5.2 Total Quality Control (TQC) In the 1950’s, the concept of TQC emerged in the U.S.A., According to TQC, besides the people connected with the actual production, others who are in the organisation in various capacities, are also responsible for quality. Though the concept had its origin in the US, the Japanese were the first to implement it with extraordinary success. In a nutshell, the company personnel involved in planning and taking decisions were now to be under scrutiny. Among the company functions which were involved in this process were the commercial office, the accounting department, production scheduling division and the design department. Involvement of company organization led to considerable quality improvement. The search for a still wider base, however continued and led to the concept of total quality management. 13.5.3 Total Quality Management (TQM) TQM was introduced towards the end of 1970’s and became popular during 19801990’s. It is an extension of TQC and quality management (considered as a Physical
variable) with human variable. It followed the notable success of the Japanese industry which had prospered following the principle of TQC. According to TQM, quality is affected mainly by the viewpoint of those working in the organization. Moreover, the measure of quality is not permanent. The organization’s vision keeps changing and so does the thinking on quality. Hence physical and human factors must work together. The factors which affect quality include raw materials, process, personnel, technical knowledge, specifications, standardization and testing etc. All these must work in tandem.
Self-check Questions 5.
How was the base of testing enlarged when moving from craftsman’s approach to SQC?
13.6 Role of Standards in Quality Control This is an age of standardization and in a globalised economy, harmonizing or rationalizing the diversity among national, regional and international standards is of utmost essence. The standards may be for product quality or for performance or may be related to units of measurement, health, safety, etc. The well known ISO 9000 series is a set of five individual but related international standards on quality management and quality assurance. ISO 9001 covers design, manufacturing, installation and servicing systems and it accounts for 20 elements of company operations. ISO 9002 covers production and installation. ISO 9003 covers only final product inspection and test. ISO 9004 gives guidelines for quality management and Quality system elements. Both large and small companies with international business perceive the ISO 9000 series as a route to open markets and improved competitiveness. Being registered for ISO 9001, 9002 and 9003 means having an accredited independent third party conduct an onsite audit of your company’s operations against the requirement of the appropriate standard. Upon successful completion of this audit, your company will receive a registration certificate that identifies your quality system as being in compliance with these standards.
Activity 2.
List some advantages that may accrue to companies that have obtained ISO certification.
13.7 Assignments 13.7.1 Class assignments i) Describe how the ideas on management of quality developed between 1930 to 2000. ii) What is ISO 9000? 13.7.2 Home assignment i) Give a clear idea of what is meant by quality and how does standardization help in quality management.
13.8 Summing Up Some basic concepts of textile testing like the meaning of quality and its importance, the approaches for management of quality which include statistical quality control, total quality control and total quality management and the role of standardization in terms of ISO 9000 are dealt with in this lesson.
13.9 Possible answers to Self-check Questions 1. Fill in the blanks: i) Planned, Tested ii) Shrink, colourfast 2. Durability, reliability, serviceability, performance, features, conformance, aesthetics and perceived quality. 3. Where the product quality is much above the required level. 4. Where the product quality is much below the required level. 5. By moving from the worker, to the production process and people involved with production.
13.10 Terminal Questions 1. Write an essay on ‘The need for quality management’. 2. How will you proceed to ensure that a product is as per the required specifications?
13.11 References 1. Mehta, P. V. 1999. Quality Management: An overview of progress in textiles; Science and Technology, Vol I, Testing and Quality Management, Edited by Kothari, V.K. IAFL Publications, New Delhi. 2. Garvin, D. A. 1998, Managing Quality: The strategic and competitive edge, The free Press, New York. 3. Juran J.M. and Oth. 1988. Quality Control Handbook, 4th Ed. McGraw-Hill, Inc., New York. 4. Frey, M. and Klein W. 1995. Quality Consciousness and New Management Structure. Zellweger Uster (Switzerland) Publication SE 498. 5. Kothari V.K. 2000. Textile Quality: An overview, in Quality control, 2000, Ed. V.K. Kothari, Textile Deptt., IIT Delhi.
13.12 Suggested Further Reading 1. Booth J.E. 1996. Textile Testing. CBS Publishers and Distributors, New Delhi.
13.13 Glossary 1. Framework
The underlying structure
2. Extensibility
Capable of being stretched or opened out
3. Superfluous
More than is needed, desired, or required
4. Aesthetics
A philosophical theory as to what is beautiful
5. Downstream
Away from the source or with the current
6. Tenacity
Persistent determination, strength
7. Mooted
Think about carefully; weigh
8. Drastic
Forceful, extreme and rigorous
9. Personnel
Group of people willing to obey orders
10. Neps
Small knots of tangled (dead or immature in case of cotton) fibres, especially in cotton