Fossilized by Amalgamma [Alvaro Lopez Rodriguez, Francesca Camilleri, Nadia Doukhi, Roman Strukov]

FOSSILIZED // AMALGAMMA

Wonderlab :: Research Cluster 4, 2014-2015 Graduate Architectural Design

UCL, The Bartlett School of Architecture

WONDERLAB :: RESEARCH CLUSTER 4, MANUEL JIMENEZ GARCIA, GILLES RETSIN Amalgamma :: Francesca Camilleri, Nadia Doukhi, Alvaro Lopez, Roman Strukov

CONTENTS

1 INTRODUCTION

5

2 MATERIALISATION

15

3 DIGITAL PROTOTYPING

41

1.1 Research Context 1.2 Research Question 1.3 Fossilized 2.1 2.2 2.3 2.4 2.5 3.1 3.2 3.3 3.4

Initial Material Testing Powder Printing Technique Supported-Extrusion Technique Robotic Simulation Linear Logic Combinatorics Pattern Logic Structural Growth From Voxels to Lines

4 FABRICATION DEVELOPMENT 4.1 4.2 4.3 4.4 4.5

95

Fabrication Workflow The Tool Motion Robotics 3D Printing Process

5 ARCHITECTURAL SPECULATION

117

6 LARGE SCALE PROTOTYPING

139

5.1 Scaling-Up 5.2 Re-thinking Prefabrication 6.1 Vase 6.2 Table 6.3 Column

1 Introduction

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RESEARCH CONTEXT 3D Printing Concrete Architecture

Why Concrete?

3D printing is one of the many technologies of the digital age that is revolutionising the world of design.

Today, the use of 3D printing technology may be seen in a vast range of research and practice areas, ranging from bio-medical engineering, product and industrial design, material science, fashion design, furniture and interior design, and up until recently, architecture.

Most of the successful outcomes of 3D printing so far have been at the smaller scale, yet there has been a thriving interest in scaling-up the 3D printing technology to produce large-scale elements, and what may be seen from very recent developments, even full-scale architecture.

At the architectural scale, concrete is one of the most researched materials for 3D printing. Concrete is certainly not a ‘new’ material when it comes to architecture. It has been available to us as quicklime or pozzolana since the times of the Romans and has remained as one of most pervasive materials in the world due to its material qualities, such as its high compressive strength and its need for little maintenance. It does not rot, corrode, or decay, is firesafe and is able to withstand high temperatures.

From a 3D printing standpoint concrete is an ideal material as, on the contrary to steel, wood and other common building materials, in its composition offers the malleability to create large continuous pieces that

need little joinery. Other benefits include its scale, the material is architectural in itself and it behaviour as a ‘liquid stone’ that is highly moldable and versatile.

Thus concrete can offer quick formal results: due to its viscosity that can be molded quite rapidly and settles relatively quickly into a load bearing, high in compression material.

The final result is all about the recipe or the ‘mix’ and the quantity of additives necessary depending on the technique used to create it. By changing the ingredients and the ratios of water, cement, aggregates and additives in the mix, its density and composition can be manipulated to create different surface textures and finishes, of different thicknesses and overhangs. These have great impact on the end result whether it is the small scale piece or the large scale volume.

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Img.1: Vassar College Courtyard by Erwin Hauer Available from: http://erwinhauer.com/eh/installations/vassar-college-chicago-hall-poughkeepsie-ny [Accessed 19 August 2015].

Img. 2: TWA Flight Centre by Eero Saarinen Available from: http://co1nc1dence.tumblr.com [Accessed 15 August 2015].

Img. 3: Standard assembly by WinSun Available from: http://www.core77.com/posts/26858/China-onthe-Forefront-of-3D-Printed-Housing [Accessed 15 July 2015].

Img. 4: Concrete 3D printing by WinSun Available from: http://www.yhbm.com/ [Accessed 15 July 2015].

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RESEARCH CONTEXT 3D Printing Concrete Architecture

Precedent Studies

As mentioned earlier, 3D printing in the architecture world is recently transitioning from its use as an architect’s representational tool to producing full-scale architectural elements and building components.

Large-scale 3D printing is becoming extremely relevant in the construction industry, where many aspirations are steering construction practices towards automation and digital fabrication; these being the desire to reduce manual labour, to reduce time and production costs, to reduce waste, to increase safety conditions and to increase architectural freedom. 3D printing has thus joined the set of tools available on the market that satisfy these requirements (Perkins & Skitmore, 2015).

When it comes to 3D printing architecture, the current leaders in the field include Contour Crafting, WinSun Decoration Design Engineering Co. and D-Shape; the former two being extrusion based processes and the latter being powder and binder based. These entities all make use of a form of cement as their base material, each one specifically adapting the traditional construction material to efficiently work with their innovative additive printing techniques. The three practices, although operating in different ways, are all driven by the prime factors of speed and efficiency.

Dr. Khoshnevis, the creator of Contour Crafting, in fact claims that with his technology it is possible to build a whole room in an hour or a 200 square metre singlestorey house in one day (Perkins & Skitmore, 2015).

Contour crafting has been developed as an on-site system, where a crane-mounted machine would build up the building in place one layer at a time (Khoshnevis, 2004).

The Contour Crafting system of printing in situ has its advantages, as it enables continuous printing and does not require any transportation and manual assembly of components, which are typically very heavy to lift and move. However, apart from the difficulty of hardening and curing the sensitive printed material in fluctuating site conditions (Perkins & Skitmore, 2015), a major constraint with this technique is the size limitation of the machine itself. In order to 3D print a building as one continuous monolith, as is done in small-scale 3D printing, the on site 3D printer must be larger, or must have a larger span, than the footprint of proposed building. Constructing and transporting such a large machine to site is not always viable or sensible, thus in such cases a ‘prefabrication’ approach might be preferable. WinSun and D-Shape have in fact adopted the off-site production process, where building components are 3D printed in a factory using a gantry mechanism and later transported and assembled on site. Through such an approach, the 3D printed construction is no different to traditional architectural construction, as it becomes a question of an assembly of discrete components.

Perkins, I. & Skitmore, M. 2015. Three-dimensional printing in the construction industry: A review. International Journal of Construction Management. [online] .Taylor & Francis Online, 15(1), pp. 1-9. Available from: http://www.tandfonline.com [Accessed 9 July 2015].

Khoshnevis, B. 2004. Automated Construction by Contour Crafting - Related Robotics and Information Technologies. Automation in Construction, 13(1), pp. 5-19.

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Img.5: Contour Crafting Insitu 3D Printer by Dr. Berokh Khoshnevis Available from: http://inhabitat.com/usc-professor-receives-nasagrant-to-develop-3d-printed-space-homes/ [Accessed 29 April 2015].

Img. 6: 3D Printed Apartment Block by WinSun, Shanghai Available from: http://3dprint.com/38144/3d-printed-apartment-building/ [Accessed 15 July 2015].

Img. 7: D-Shape Print Available from: http://www.shapeways.com/blog/archives/2173d-printing-buildings-interview-with-enrico-dini-of-d_shape.html/ [Accessed 19 August 2015].

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Img.9: 3D Printed Wall-Window Assembly Available from: http://3dprint.com/2471/3d-printed-home-in-minnesota/ [Accessed 15 July 2015].

Img. 10: 3D Printed Wall-Window Detail Available from: http://futurecities.org.uk/2015/03/24/3-d-printedhouses/ [Accessed 15 July 2015].

Img. 11: 3D Houses in Shanghai by Winsun Available from: http://www.theguardian.com/cities/2015/ feb/26/3d-printed-cities-future-housing-architecture#img-3 [Accessed 15 July 2015].

RESEARCH QUESTION Questioning Mass-produced 3D Printing

Aesthetics vs. Speed Of Construction

After examining current large-scale 3d printing examples it can be concluded that although extremely revolutionary and advanced as processes, unfortunately the results created may be regarded more as stagnant construction assemblies than as true architecture. Despite striving for innovation, so far the final constructions are still clearly traditional from an assembly standpoint; where elements prescribed to specific requirements, such as apertures, roofing or thermal insulators, are being ‘plugged’ into the final concrete assembly, just as in regular construction approaches.

Whether adopting a continuous or a discrete method of production, whether a prototype or actual construction, the existing 3D printed architecture examples or proposals so far seem to be using their 3D printers as a regular mass production machine, still following the factory model. The buildings they are producing appear to be standardized, ‘cookie-cutter’ products – they are not optimized and do not follow any design logic or aesthetic. Tin the small-scale 3D printing sector, is still not present at the architectural scale of 3D printing.

With large-scale 3D printing, it is clear that the factors of cost and speed seem to be taking the favourable position in the development process, while design seems to be taking a secondary role, if considered at all.

This encourages an interrogation of the potential and relevance of 3D printing within the realm of architecture, starting with the elementary question: if one could 3D print anything, what would one print?

Unfortunately despite the exciting possibilities of 3D printing new forms of architecture, the potential of what could actually be created has not yet totally been materialised. This calls for the need to abandon traditional assembly techniques in favour of a completely new mode of 3D printing production and assembly.

Can we rethink typical architectural components such as walls, windows, slabs, structure, roof, etc? Is it possible to break the rigid effects of industrialisation and bring back the concept of craftsmanship through 3D printed architecture?

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FOSSILIZED Overview

Research Statement

The project attempts to counteract the current ‘stagnant’ 3D printing practices mentioned, aiming to reinstate the concept of craftsmanship back into architectural design by adopting a more tectonic approach to 3D printed form. Rather than focusing on actual form generation, this is achieved through an understanding of aggregation and heterogeneity at the material level, encouraging the dissolution of boundaries at the massing, structural and material scales.

To achieve this, a fabrication method was developed that combines two already existing concrete 3D printing methods: the extrusion printing method, and the powder printing method. This combination of techniques has given rise to a form of supported extrusion, whereby the concrete is extruded layerby-layer over a bed of support material. Due to the support, the resulting extruded concrete is of a much higher resolution with larger overhangs than the results produced by the current practices studied. The supported extrusion method has therefore presented the opportunity to design forms that are more varied and more volumetric, as opposed to the very straight vertical forms so far achieved in practice.

At the core of the project lies the computation of a linear fabrication tool path, having a varied material deposition, altering the material density according to stress alignment and light qualities, where the mixed deposition of concrete and translucent/transparent

material gives rise to the structure and surface articulation, which in turn gives rise to the overall form and design language of the project.

Fossilized also aims to challenge standardised concrete prefabrication techniques by questioning the nature of the fabricated piece. Although 3D printing a whole structure from start to finish may not be possible due to fabrication constraints, it could be possible to print, for example, a floor-wall-ceiling assembly or a stairfloor-wall assembly as one whole architectural chunk – each chunk equally designed as a unique object capable of existing independently. This is redefining the concept of the catalogue construction element, which has been instilled on the architecture industry by massproduction. These chunks could be assembled on-site, as is done with traditional prefabrication techniques, however their tectonic qualities would be completely different.

Through a combination of heterogeneous chunks that are fabricated by varying the properties of the material through a linear tool path at every layer printed, it becomes possible to reduce material, save time and also achieve a design that is evokes continuity, structural directionality, design hierarchy, density variation and multi-materiality and continuity in a single form.

Amalgamation of Wall and Window

RESOLUTION

Bringing back craftsmanship- aiming for the highest possible resolution

CONTINUITY

Dissolution of boundaries- continuity of design, structure and material

DUALITY

AMALGAMMA

Amalgamation of the translucent and the opaque- creating a multimaterial system

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2 Materialisation

17

INITIAL MATERIAL TESTING Introducing Translucency

Material Merging

In reality, with 3D printing, there is no specific need to create out of solely one material, because of the nature of the process. We can start thinking of a multi-material system that involves a secondary material. In order to dissolve architectural components (such as wall and window), testing different transparent materials and their relation or non- relation to concrete became an elemental driver to our research.

Typically windows are made out of glass, and glass like concrete is not a material found in nature. It is created industrially and is typically transparent, light and operable for fenestrations. It is conceived as a separate entity or a plug in, because of its standardized form. In reality, whether in traditional, or in emerging 3D printed buildings, the usage of glass panels restricts architectural design and our intent of dissolving the boundaries between what is opaque (concrete) and what is transparent (glass).

We have opted for experimenting with transparent or even translucent materials that still diffuse light through in liquid and powder form. We have experimented with silicone, glass beads, glass powder and finally rock salt.

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POWDER PRINTING TECHNIQUE Initial Fabrication Method

materials

Printing Method

sand

silicone

PVA

water

polymer

tools

binders

cement

sprayer

additives

syringe

fibres

powder additives 20

layer 1: hardening binder dropped onto powder

final layer: model hardening in support material

layer x: layer by layer process & piece is built up

excavated hardened model from within powder

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Manual Water Dropping

Manual Water Dropping - Excavation

Sprayed Water Powder Printing

Sprayed Water Powder Printing

Sprayed Water Powder Printing - Excavation

Sprayed Water Powder Printing - Excavation

Sprayed Water Powder Printing - Excavation

Sprayed Water Powder Printing - Excavation

23

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Powder Printed Model Reinforced with Fibre Additives

Powder Printed Model with the Use of Only Cement Powder and Water

Powder Printed Model with the Use of Glue as Binder Material

In order to test the maximum strength of a powder printing method with concrete, we made various material experiment. Those were done with different ratios of sand and cement as well as the use of glue in the hardening process and fibres in the mix.

The results we excavated were all relatively weak and were not strong in compression and were collapsing very quickly. These is the main reason that pushed us to experiment with other fabrication methods.

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Example of a Powder Printed Model Cracking

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SUPPORTED-EXTRUSION TECHNIQUE Chosen Fabrication Method

materials

Printing Method

sand

water

support

cement

rock salt

PVA

UHU

binders

glass beeds

concrete extruder

glue extruder concrete extruder

layer 1: extruding ready mix concrete into a layer of translucent support material

layer x: layer by layer building up of an extruded piece, while binding support material to the model concrete

support material

final layer: model hardening in support material

excavated hardened dual material model from within powder

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First test of Supported Extrusion

As powder printing tests showed, the way concrete and water are mixed is crucial. Extrusion works with already mixed components of concrete, therefore the chemical and the concrete is stronger. Considering the advantages of the 2 methods, we decided to combine both. For next material tests, we mixed sand, cement, and water, and used sand as a support material. First results showed that the method is promising: they were strong, had variations in forms, quite high resolution for manual printing and had cantilevers, which, specifically, proved ability of layers to distinct and have variations of surfaces that are impossible for extrusion without support.

Another important material and structural aspects of the research are porosity and translucency within concrete

structures. In an attempt to incorporate translucent material into concrete printing process, the team decided to try some translucent powder-like materials: salt, glass beads. They were deposited on each layer, according to translucent zones in printed objects, and, then, glued with a binder. Results showed that this technique works. Yet, this process supposedly might have caused problems with identifying areas for translucent materials. At this time, there were two materials, apart from concrete – support(sand) and translucent. We then, decided to replace sand with translucent material, so they are no longer two separate players of the game, but only one.

Support is translucent and, with binder, may transform into part of the structure. Thus, this transformation makes translucent support as changeable as “liquid stone�.

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PVA 1:3

rock salt

E600

PVA 1:3

E600 glass beads

UHU

Design Tech

UHU

Design Tech

PVA 3:1

Super PVA 5:1

PVA 3:1

Super PVA 5:1

PVA 5:1

Super PVA

PVA 5:1

Super PVA

First Model of Dual Materials: Concrete Supported Extrusion, Hardened Rock Salt and Glass Beads

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ROBOTIC SIMULATION Manual Printing

Minimal Surface Inspiration for Concrete Supported Extrusion

Second Variation of Manual Robotic Simulation

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With the method developed, we set out to 3D print a 1x1x1m object inspired by minimal surfaces: geometries that are self supporting with a strong centre core (Img.1) and that are usually a demonstration of very thin structures with large spans of overhang, a quality that we wanted to achieve with supported extrusion in concrete (Img.2 & 3).

In order to do so, we made the first manual experiment mimicking the future robotic fabrication with the aid of a bounding box and the support material, for which we used salt as support. The use of salt is also beneficial because, once the concrete model hardens, the salt can then be washed off and dissolved in areas that are not part of the design.

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Result of Manual Robotic Simulation

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LINEAR MOTION Computational Investigation

All the previous materials we experienced through initial tests (powder printing, extrusion on the powder support) showed that technically to create any volumetric object we need to have, as the final outcome of the computational logic, the linear two-dimensional movement. It requires taking into account that line cannot intersect itself as the doubled deposition of the concrete can cause future problem for the precision and perfection of the printed object. In addition, the speed of the deposition of the concrete may vary depending on the consistency of it. Consequently, the start and the end of the deposition may not happens exactly at either the start or the end of the line.

Therefore, the lines (toolpath) for deposition should be as long as possible, so any delay or problems occurring at the start\end points will not cause serious deformation of the whole printed layer.

First, we tried to investigate some examples of computing linear logic, such as Self-Avoiding Walk and Traveling Salesman problem. They showed that any volume either it is generated or designed manually at the level of toolpath is a collection of points on a section plain for every layer. All these points are like cities on the route of a salesman. Thus, toolpath should represent the shortest and continuous way – the longer total distance the more time fabrication takes.

Second, we started to experiment with coding aiming to create a system that generates toolpath in an existing 3D field of points. The system also read the stress data that we imported into background database, thus the computational logic have an opportunity to decide how dense the line should be in a certain areas of the created object.

Simultaneously with computational experiments, we tried to simulate the linear robotic motion manually. The toolpath for this was created with the simple slicing of the model that gave us planar contours with a specified step along z axis. However, as 3d printing allows to go beyond the fabrication limits, we wanted to go far from just slicing the models. Thereby, contours are not solutions for toolpath.

Yet, the first computational experiment with a chair turned out to be a close relative to the contouring technique. It just deformed the original volume, giving it distinction in porosity. Any deformations with a 2d line are just modifications that are applied to the object, but we wanted more. We realized through these experiments that computational logic should create toolpath based on the volumetric conditions created within this computation itself. Only generation volume from scratch will provide a ground for the successful toolpath generation.

Stress data (left) and toolpath generation according to the stress - around stress lines the code creates more dense parts of the toolpath, and more porous in the rest of the model.

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3 Digital Prototyping

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COMBINATORICS Form Generation

Combining Minimal Surface Units

Combinatorial design theory is a part of combinatorial mathematics that works with systems created out of finite sets of building blocks. This set cannot change, modify or mutate. The system organization is based on repetitive building block, which can be a single type without any variations. As part of our form generation we began to explore the use of combinatorics to building up a volume using a single unit. Since our manual printing experiments proved that we could achieve thin, cantilevering surfaces with our printing method, we created a combinatorial unit that exhibited minimal surface-like qualities.

We therefore began to explore the combinations of this surface unit (24 rotations), analysing the possible connections and design qualities that can be produced through different combinations. We learned that even though the unit is simple it can create design complexity through different combinations. In order to enrich the level of complexity and variation however, we

created a set of different units that vary from more solid and structural to more porous and translucent. We also created units for different edge conditions that would vary according to their situation, such as floor edges, wall edges and ceiling edges. Thus, structural stability, material and density variation might be achieved with a finite set of blocks.

A computation logic for combining the units was developed based on the unit connectivity and rules for fitting. This connectivity was established through the use of a skeleton that represents the surface unit. By setting up these skeletons in a voxel space, their connections could be computed based on the designed rule-set to generate the final form. We experimented with two scenarios, one where the form outline is defined and then articulated through the unit combinations and the other where the form is built up from a single unit and left to grow almost infinitely according to the defining rules.

Minimal Surface Combinatorial Unit

Unit Combination Examples

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The Skeleton Unit

Computational Connectivity of Surface Skeletons

Edge Condition Experiments Varying the shape of the surface units according to their position on the floor, wall or ceiling

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Chaise Longue Prototype Varying surface units according to edge conditions and porosity/density

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Layered Column Elements Applying a second level of computation to the generated form, the

fabrication

in the form of

layer-by-layer

toolpath

generation

51

Architectural Exploration Applying the combinatorial and toolpath generation system to the architectural scale

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PATTERN LOGIC Form Generation

Aligning to Structure

Although created from a set of different units, until this point, the resulting design still lacked the desired level of variation, directionality and hierarchy. For this reason we adapted the unit from a surface skeleton to a linear skeleton that is comprised of directional and nondirectional lines, still within the voxel.

The driver for the computation is no longer the question of physical connectivity between surfaces, but rather the alignment of these directional elements to structure. With this unit, the combinatoric logic now relates directly to the material organisation, as the unit not only dictates the volume’s internal structural optimization, but it also is designed to generate the volume’s surface articulation. The result is the formation of a visual pattern of structural ‘ribs’ on the surface of the base form. These skeletons are later given volume through a second computational process and variably thickened internally according to the different requirements of structural rigidity within the form.

The new unit set consists of four types, each embedded with their own material ID and directional properties. These are combined according to the stress

data in the volume and connected to create continuous patterns on the surface, that vary in opacity, linear density and porosity.

The process involved in computing the combination of these units first starts with the voxelisation of a base model, with the resolution of unit (approximately 200mm). After structural analysis of this model, it is filled with the skeleton units all facing the same direction. The units then read the environmental conditions (stress information and the rotation of their neighbours) and rotates to align with the main stress direction. By rotation, skeletons try to align with stress lines and to connect into continuous pattern that emphasizes stress direction. The function for identification what type of the skeleton should a voxel choose is distance of a voxels to the stress lines and vertical position of it (the higher the more porous).

When all voxels chose their suitable skeletons and all structural skeletons are aligned and connected, there is a step of pattern fixing. After first manipulations, only structural skeletons are fixed. All others need to rotate to connect to surrounding skeletons to create continuous pattern. Rotation happens randomly until a skeleton meets conditions of successful connectivity (the number of common points on edges).

The Surface Skeleton Unit

The Linear Skeleton Unit

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Pattern Skeleton Voxels

Manual Pattern Experiments Manually drawing and thickening skeleton units to form different surface patterns that could potentially follow the main stress direction of the volume.

Thickened Skeletons

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Pattern Skeleton Voxels

Manual Pattern Experiments Manually drawing and thickening skeleton units to form different surface patterns that could potentially follow the main stress direction of the volume.

Thickened Skeletons

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Concrete Voxel Directional Structural Rib

Translucent Voxel

Non-Directional Infill

Multimaterial Voxel

Semi-Directional Gradient Infill

Concrete Voxel Directional Emphasized Edge

The Pattern Skeleton Unit Set

1.Identify Main Stress Lines

3. Assign Voxels Direction Axis

2.Voxelise Volume

4. Calculate Priority Direction

Finding Pattern Alignment Direction The direction of alignment is based on the angle between the stress direction and the voxel main axis. The axis which shares the smallest angle with the stress direction is the priority direction of alignment.

1. Alignment and connection

2. Infill alongside structural ribs

of concrete skeletons to form

with mixed material skeletons

continuous structural ribs

to create a gradient between the two materials

3. Infill of non-structural translucent skeletons

4. Addition of structural edge skeletons to emphasize certain edges

Aligning to Priority Direction After identifying the structural voxels, the structural skeletons are imported into the voxel space and rotated to align to the priority direction accordingly. Once aligned the breaks in the pattern continuity are identified by checking the skeletons of the neighbouring voxels. The problem areas are once again rotated until a connection between the skeletons is found.

Identifying and Connecting Disconnected Skeletons

Infilling Non-structural Voxels with Mixed and Translucent Skeletons

Table Prototype - Pattern Generation - Top View

Table Prototype - Pattern Generation

Table Prototype - Thickened Skeletons

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PATTERN LOGIC Form Generation

Pattern Generation Process - Prototypical Column

Main Structural Lines

Concrete Skeletons

Concrete Edge Skeletons

Structural Skeletons

Translucent Non-Structural Skeletons

Combined Result

Varying the Voxel Scale In order the increase porosity and add variation to the pattern, the voxel can be scaled to different sizes that still allow for pattern continuity yet add differentiation to the pattern.

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STRUCTURAL GROWTH Form Generation

Initially, the idea of volumetric growth derived from the will to avoid any modelling of any form. The reason of it is a mind of a designer who works on an object of any scale. On the one hand, modelling is supported by designers’ creativity that allows an object be as suitable as possible for specific task and in a specified environment.

However, such approach does not provides a system to generate object of any scale for any environmental conditions in a short period of time. Any systems beats personal approach with time cost of the work to be done for a project.

Investigating different computational ways of generating systems, the Amalgamma team had experimented with voxels and Cellular Automata (CA). Cellular space allows the research team’s computation strategy to provide huge amount of calculations at the same time.

128 mm

72 mm

32 mm 24 mm 16 mm

8 mm

24 mm

40 mm

40 mm

40 mm

24 mm

40 mm

56 mm

56 mm

56 mm

CA is based on a neighbourhood that, consequently, lets the whole system deals with local calculations disregarding all other calculations of others neighbourhoods of points in a 3D array.

To create a volume means to grow it. The growth of the Amalgamma team is based on the simplest decision that can happen in the array - “to be or not to be”*.

Different types of neighbours activation (growth) for concrete (above) and translucent (below).

72 mm 48 mm

The desire to generate surface-like volumes pushed the research team to create rules in the 3D array that activate a different number of neighbours to create a profile regarding to structural conditions.

32 mm 24 mm 16 mm

40 mm

40 mm

40 mm

24 mm

8 mm

56 mm

56 mm

56 mm

40 mm

24 mm

* Hamlet, William Shakespeare.

Translation Pattern into Voxels

Growth of the Inversion of the Volume

Growth of the Volume

Final Volume

Growth of the strongest structural part of an object

Growth of the surface like translucent part to create more flat parts

Growth of the surface like translucent part of an object with a middle depth Growth of deep translucent part of the structure

Growth of the flat parts of the structure Growth of the structurally stable and deep surface-like volume

All variations of growth create thin surfaces with a profile of a sliced pipe with a different depth. These “pipes” are generated according to the pattern that, after generation of the whole pattern “world”, is translated into the voxel world where each line of the pattern identifies the properties fro the voxels it was transformed into and, according to the data it bring within itself, decides how exactly the neighbourhood should react to it - what material are they, how deep and strong the future pipe-like volume is going to be.

Growth of One Pattern Unit

Pattern of the translucent part

Pattern of the concrete part

Pattern of the both parts

Growth of the translucent part

Growth of the concrete part

Growth of the both parts

Growth of Multimaterial Pattern

Before Elimination

Due to the box-like nature of the pattern skeletons the initial outcomes of the code generated objects had the issue with edges and deformations of an object into a rightangled volumes. To avoid this problem the research team added a step to the computational system that identifies the external voxels after if grows them and eliminate them to stick to the approximate shape of the initial model. Therefore, the distinction and independency of pattern voxels is fused into one and the sharp edge result is avoided.

After Elimination

Elimination of Extra Voxels

FROM VOXELS TO LINES Toolpath Generation

After generation the volumetric part of an object it is a collection of voxels of two materials. The object itself is a deformed 3D array of voxels. However, the fabrication logic is linear and 2D as it happens on one horizontal plane at a time (one layer after another). To deal with the 3D world of voxels the computational part of the toolpath generation slices the object with the step of the world along Z axis and take points of each layer separately. The code identifies the centroids of the voxel which are the points for the future continuous toolpath.

The neighbour logic of the voxel world maintains in the toolpath coding part as well. Each point in a layer first of all check its neighbourhood. It counts how many neighbours of the same kind (according to the material) are around. Logically, the end and the beginning of any line is the point that have one neighbour only. First computational test showed that sometimes in a generated layer points with single neighbour do not exist at all due to high density of the

layer. Consequently, the code looks for points with less or equal of 2 neighbours around and gives them the priority to start the line of the toolpath.

These points start to investigate the surrounding and connect themselves to other points. Each point might have maxim 8 neighbours, thereby, 8 connections. Yet, to create a continuous line each point should have only two connections. Thus, the code identifies not only are neighbours have been already connected or not, but also how many connections the point has. If number of connections is two, the points stop to look for any other possible ways to continue the line.

The points that have been connected activate at the same time and start to do the same operations as the previous points of a layer. When all the points draw 2 lines to their neighbours, the code counts how many points without any connections are left. If the number is small, it goes up to the next layer.

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Code Checks the Number of Neighbours

0

0

12

2

2 2 54 453 465 2453

2

1

1

2

22

2

1

1 2 2302 2

0 222 5 4 2333331 23 3

23 3

2 23244 14432 11222 2

12 2 1222222222

22

2

2

2

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4 455 53 3

2

3

2 2 2 2 2

3

4 42

1222222122222 23322222223 2 3 4 4 2 32 3 3 2 2 2 3 3 2 3 3 3 21 3 2 345442 2 1 3 2 3 253 1122 2 2 3 44 55 2 2 1 2 2 2 55 2 2 1 231 2 2 2 2 2 44 2 2 0 21 2 2 2 2 2 3 23 2 2 2 341 22 4 2 2 2 32 3 31 2 2 2 2 2 22 2 2 Layer of 1 Points 3 2 4554 2 2 2 2 244553 2 342 2 3 2 14 1 3 231 32 2 2 43 2 1222 3 2 2 2 23 2233 1 2 2 2 2 4 2 01 2 2 3 53 1 2 2 3 2 2 44 54 2 32 2 1 2 3 1 21 4544453 123455 5 2 32 1 1222 2 2 2 42 3 2 2 32 3 2 1 3 32 2 3 32 3 2 21 1 32 253 43 23 2 3 3 23 3 23 4 3 23 2 2 22 3 2 23 2 1 1 1 1 2

10%

1 2

3 3

1

3 3

3 3

12

2

2 2 54 453 465 2453

2

2

2 2 2 3

3 32

2

1

1

2

22

2

1

1 2 2302 2

0 222 5 4 2333331

3 32

2

1 2

1

23 3

2 23244 14432 11222 2

22

2 232 3 2 12 1 2 1222222222

2

2

2

1

2

3

2 2 2 2 2

3

3 4 4 42 2 455 3 53 1 2 232 2 232 1 2 2 2 2 2 223 3 2 2 2 2 2 2 2 3 3 3 4 2 3 4 4 4 4 2 3 3 43 32 2 3 42 2 2 32 4 3 2 3 3 3 2 1 33 2 345442 2 4 1 3 253 2 34 4 2 2 4 21122 2 3 52 5 2 2 22 2 23 2 1 2 2 2 55 2 2 2 1 231 2 2 3 2 2 2 2 44 2 0 2 2 3 22 2 2 1 2 2 3 2 2 2 3 1 22 2 2 341 3 22 4 2 2 32 3 2 31 22 2 2 2 2 2 22 2 1 3 2 2 2 4 55 55 4 2 2 12 2 2 2 2 2 2 3 3 4 4 4 12 2 3 14 1 3 231 32 2 2 423 2 2 2 2 1222 3 2 2 2 23 2233 1 2 2 2 2 4 2 01 2 2 3 53 1 2 2 2 3 2 2 2 2 4 41 54 2 32 2 3 1 4544453 2 21 1 123455 5 2 32 2 1222 2 2 2 42 3 2 2 2 32 3 1 3 32 1 1 2 2 2 2221 3 32 3 2 21 1 32 253 43 23 2 3 3 23 3 234 3 23 2 2 22 3 2 23 2 1 1 1 1 2

1122221 2 2 1 of Neighbours Number 1 2 2 2 2 21

1 21 2 2 3 2 32 2 1 1

1 2

3 3

1

3 3

3 3

3

2

3

4 42

2

3

2 2 2 3

4 42

3

3 32

3 32

2

1 2

44 2443 3

1

2 2

2 2

1 1

2 23 22222 2 3 2 2 23 2 1 3 2 2 2 22 21 1 2 222 2 2 2 2 2 1122221

1122221 2 2 1 1 2 2 2 2 21

1 21 2 2 3 2 32 2 1 1

11 22 2 2 2 22 2 2 2 2 3 2 32 2 2 1

of Each Point

0

Check of the Points Left

Final Toolpath

11 22 2 2 2 22 2 2 2 2 3 2 32 2 2 1 0

Code checks the number of neighbours in the first place (before drawing the toolpath). When the toolpath is drawn code checks the number of points in the layer that are not connected to any of other points. Code calculates the number of all points in the layer.

If the number of left points are less than 10% of the whole numbers - the toolpath is successful and code can go up to the next layer.

Neighborhood Data of Each Point

83

Toolpath Generation

Toolpath Catalogue Layer by Layer

Toolpath Catalogue Layer by Layer

87

FROM VOXELS TO LINES Toolpath Generation

Entire Computational Workflow

Pattern Generation

Volume Generation

Toolpath Generation

Final Volume

89

Img.01

Img.02

Img.03

Img.04

Through different design experiments we paid a lot of our attention to the issue of the border. As the pattern has a box-like nature it automatically creates a rightangled edge to any, even very smooth, shapes. We tried different approaches. First (Img. 02) we tried to erode the resultant linear edge manually, but realized that this approach is time expensive and does not let to deal with edges on a bigger scale. This approach definitely can be a part of a computational system.

Consequently, we let the toolpath be responsible for edge deformation (Img. 01, 03, 04).

91

93

95

4 Fabrication Development

97

FABRICATION WORKFLOW Robotic Supported Extrusion

Our developed supported extrusion method gives a new dimension to concrete 3D printing. This method allows, thanks to the support material, to print multi-material based pieces. This concept created in the idea of using glass beads/rock salt as support material and use the logic of powder printing at the same time with extrusion to bind glass and extrude concrete with the same tool. In order to achieve this we have developed a combined dual material nozzle of concrete and binder material (glue) which connects to an industrial robot and print both materials in the same routine. The result of this, is an innovative piece of architecture with structural performance, and a translucent effect achieved.

The main goal is to achieve the optimization of material through the fabrication process in relation to the design process, allowing for a high control in the printing and performance with a very unique finish of the various objects printed .

Glue Hose

ABB 1600-145

Concrete Mixer Concrete Hose

Wate r

Sharp Sand Concrete Container

Cement Bounding Box

Peristaltic Mortar Pump

Glue Nozzle Dropping Control

Motor Base Support Concrete Pressure

3D Printin g

Concrete Nozzle

99

FABRICATION WORKFLOW Robotic Supported Extrusion

Bounding Box Perimeter 500mm

The Bounding Box

The Supported Extrusion method is framed by a bounding box as the limiting size for every piece. For the 3D printing process we use a bounding box based on the maximum reach of the industrial robot, used in the fabrication process.

700mm 1000mm

Structural Frame

The Bounding box is designed in 3 parts to easily extract the model after printing. The main piece is the bounding box perimeter that defines the real 3D printing volume. Attached to this perimeter, there it is the structure frame that holds the stress and contains the support material to reduce the wasting. The third piece is the printing base, which gives finalizes the texture to the top layer and works as structure during the hardening period. For the texture we use different materials as plastics woods and metal to achieve a sort of finishings depending on the purpose of the printed piece.

Printing Base

800mm Bounding Box assembled

1200mm

Layering Support Material

The supported extrusion method developed requires a support material in order to achieve overhang and push the material to its full capacity.

Support material in our project acts at the same time as a translucent material to combine opaque and translucent.

Material: ABS Pelets Size: 3-5 mm diameter

During the research many different materials were tested to find the most accurate in terms of translucency, resistance, homogeneity and price.

For the layering, we designed a system of two kinds of layers, the main layers related to the toolpath and extra layers of filling material. The redensification is due to the need of reinforcement needed for the layers.

Material: Glass Beeds Size: 1.5-3 mm diameter

Layering System

Material: Rock Salt Size: 2-4 mm diameter

500 mm

x 20 Main Layers x 40 Densification Layers

Densification Layers

Main Layer

Material: Crushed Glass Size: 1-3 mm diameter

Layer Thickness: 8mm 101

THE TOOL The Glue Nozzle

Support material has two different roles in the 3D printing method. Apart from its use as support for the concrete, it also behaves as a translucent material that binds together and with the concrete, creating a window type effect.

This binding system is formed by compressed air circuit that controls the binder dispenser. The glue used in the nozzle is based on acetone and silica. The result is a homogeneous composite of waterproof and translucent material combined with the concrete behaving as a the non structural support material.

Compressed Air Circuit Glue Deposit Glue Attachement Nozzle Valve

Binder Allowance

Compressed Air Controller

Nozzle Deposit

Robot Connection Box Nozzle End Joint Nozzle Head

103

THE TOOL

The Concrete Nozzle

The 3D printing method for concrete is based in a extrusion system. In order to print, it is necessary to use a tool to control the flow of material from the pump.

The solution we researched is a concrete nozzle base in a traditional extrusion method with an outlet that gives the final resolution.

To achieve a functional tool we have developed different generations of the nozzle solving every problem we were encountering in the fabrication process. All these tools were designed and 3D printed themselves in ABS plastic form as to test rapidly every improvement.

Tool Generation 1

Tool Generation 2

Tool Generation 3

Tool Generation 4

Tool: empty nozzle with 35 mm D outlet

Tool: nozzle with a helicon screw & 15 mm D of outlet ..

Problems: Helicon Screw is too thick & not steady

Tool: nozzle with a Steel rod & 15 mm D of outlet ..

Problems: Very difficult to control the flow and no control of the resolution extruded

Tool: nozzle with a Steel Rod inside 10 mm D of end ..

Problems: Problems with concrete hardening and clogging the chamber

..

Problems: Concrete cloggs inside if there is no rotational force pushing the concrete out

105

THE TOOL

The Concrete Nozzle

Robot Junction Stepper Motor Tool Junction

Glue Tool

Glue Connection

Hose Adapter Concrete Tool Attachment Concrete Entry

Glue Nozzle

Valve Attachment Glue Attachment

Concrete Valve

Concrete Nozzle End Concrete Chamber

107

MOTION

The Pumping Method The pumping system for the concrete is based in the Peristaltic Pumping Theory.

The Peristaltic pump is designed to pump thick materials like concrete with a very low energy consumption. The pump has different positions to adapt the speed depending of the necessities of the concrete extrusion.

Main Structure External Chassis

Shaft Connector

Rotor Shaft Chassis Rotor Chassis

Shaft Chassis

Motor Chassis

Rotation Hole Motor Junction

Motor Shaft Connector

s

Preasure Roller

Peristaltic Pumping Method

Pumping Concrete Out Concrete Allowance Creating Vacuum Effect

Pushing Concrete

109

ROBOTICS Printing 1 :1 Scale

The 1:1 3D printing method is based in a robot assisted method. The whole routine is designed to print pieces of actual concrete layer by layer with an ABB 1600-160 robot.

0.0_Starting Point

0.1_Home Position

1.0_First layer

1.3_First Layer 75%

1.3_First Layer 100%

1.4_Home Position 2

1.5_Pause Position

5.3_Layer Nº 5 75%

10.3_Layer Nº10 100%

15.3_Layer Nº15 50%

20.3_Layer Nº20 10%

25.3_Layer Nº25 15%

30.3_Layer Nº30 40%

35.3_Layer Nº35 45%

35.4_Layer Nº10 100% FINISHED

3D PRINTING PROCESS Fabricating

Attaching the Printing Tool

Gathering Materials

Mixing Sand & Cement

Connecting Electronics

Measuring the Amounts

Preparing the Concrete

Connecting Air Circuit

Sand Ready (10 kg)

3D Extrusion Printing

Setting the Pumping Circuit

Cement Ready (6kg)

Support Layering

113

3D PRINTING PROCESS Excavation

Once the printing process is over the model needs to be extracted from the bounding box. To start the process it necessary to leave the model drying for a safe amount of time to be strong enough for the excavation process.

When the model is dry enough ,the first step is to remove the bounding box. Then without the bounding box, the support material can be removed easily. this action is very necessary because without this step the drying process will not be completed satisfactorily .

Removing Bounding box

Removing Support Material

After removing the support material layer by layer the model needs to be cleaned with compressed air, to remove the last grains of the support material and dry the surface properly. Once all this process is finished the model needs to be moved to a very ventilated place to complete the whole process of hardening.

Cleaning Layer by Layer

Compressed Air Cleaning

Final Hardening Process

115

117

5 Architectural Speculation

119

SCALING-UP Creating Space

Chunk Design Strategy

Stress Analysis

Skeleton Alignment to Stress Analysis

Resulting Pattern

Toolpath Generation

Volume Growth

123

124

125

SCALING-UP Creating Space

Large Scale Design Strategy

Stress Analysis

Skeleton Alignment to Stress Analysis

Resulting Pattern

Toolpath Generation

Volume Growth

129

131

RE-THINKING PREFABRICATION Amalgamma Construction Strategy

In House Production/ On Site Assembly

Similarly to the previous example, the architectural speculation adopts the same strategy to the scale of a large building. The strategy will fabricate kit-off parts off site (similarly to prefabrication) in a bounding box that respects the dimensions of the transport unit: the shipping container (5 bounding boxes can fit into 1 shipping container). Those will be fabricated in a 3D printing factory and then transported and assembled on site. Contrarily to prefabrication done in series, the architectural speculation fragments architectural components not depending on their functions but depending on their topology. The pieces will respect bounding box restrictions and should all be free standing, therefore will take in account major restrictions such as maximum cantilever, maximum piece size, etc.

Another important concept is the fact that the overall strategy is generally inspired from the small scale of the continuous piece and that even the pieces themselves printed continuously will never be only ‘horizontal’ or

only vertical. The unique piece concept will tackle the issue of amalgamation of architectural components in one bounding box.

The wall does not have to be strictly a flat vertical element and the slab, a horizontal flat element; those two just like the window and the wall can vary and interplay to form a more fluid homogeneous whole.

Whether operating at the object scale, or at the architectural scale the team has accomplished to push concrete to its maximum capacities with the combination of two fabrication methods and a support material that may or may not operate as a secondary building material. The fold is favoured to the whole in the process of design due to the restrictions overseen in the overall fabrication method. It is it, that contains the window and the wall, the wall and the ceiling, or the structure and the ornamental and it is those pieces that is type of heterogeneity that ends up forming a continuous whole.

In- House Production

2.00 m

2.00 m

2.00 m

On Site Assembly

133

Volume Growth

The dual usage of material gives the research project more scope in expanding the spatial speculations that we have developed for this method. We will try and resolve the most basic questions of rethinking the method of design for architectural space with this new paradigm shift, while taking in account the current constraints of fabrication in the physical world at various scales.

If we can now fabricate continuously, then should there be a cut? If so, where should it be? Can we rethink typical architectural components such as what are the purposes of walls, windows, slabs, structure, roof, etc and does additive manufacturing drive us to reconsider? How does this project function at the architectural scale?

135

RE-THINKING PREFABRICATION Amalgamma Construction Strategy

Assembly Catalogue

Piece 01

Piece 02

Piece 03

Piece 04

Piece 05

Piece 06

Piece 07

Piece 08

Piece 09

Piece 10

Piece 11

Piece 12

Piece 13

Piece 14

Piece 15

Piece 16

Piece 17

Piece 18

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138

This research project is a direct response to recent advancements in additive manufacturing. The technology is currently on a gradual leading course to becoming soon mainstream and eventually transforming the construction industry that has been quite unchanging since more than a century ago. Many of the users are looking into the 3D printing of concrete on a large scale due to its various beneficial properties and its architectonic scale.

The material, is however being restricted to its maximum capacities, and is nevertheless being used mainly at a standardized mode of production, similarly to traditional design and construction methods. The tool of fabrication is essential in the process of what is being outputted and should inform the design method and process at internal and external levels.

In reality, the feasibility of our outputs are based on this approach where material and fabrication method precedes formal obsession, and it is the structuring of material properties as a function of structural and environmental performance that generates the design form. By taking in consideration external factors such as time, temperature, and structure as a simulation of environment, and adding structural loads, the optimization diverges the initial form into a secondary one that is formed in pieces, to create a whole. Our outputs are designed as heterogeneous pieces or chunks that generate the homogeneous totality. This is our approach to the phenomenon of form finding.

139

6 Large Scale Prototyping

141

Vase

Generation Process

Skeleton Lines for Volume Generation

Generated Voxel Volume

Final Result After Toolpath Generation

143

145

147

Table

Generation Process

Skeleton Lines for Volume Generation

Generated Voxel Volume

Final Result After Toolpath Generation

149

151

153

155

157

Column

Design Process

Piece 6

Piece 5

Piece 4

Piece 3

Piece 2

Piece 1

Toolpath Variation From Horizontal (Bottom 2 Pieces) to Vertical Top (4 Pieces)

159

01

02

Column Form and Density Investigation Pattern Skeletons

03

01

02

03

Column Form and Density Investigation Thickened Skeletons After Growth

161

04

05

Column Edge and Density Investigation Pattern Skeletons

06

04

05

06

Column Edge and Density Investigation Thickened Skeletons After Growth

163

Column

Design Process

Column Fabrication Pieces

Piece 1: Side 1 & 3

Piece 3: Side 1

Piece 1 : Side 2 & 4

Piece 3 : Side 2

Piece 2 : Side 1 & 3

Piece 3: Side 3

Piece 2 : Side 2 &4

Piece 3 : Side 4

Piece 4: Side 1

Piece 5: Side 1

Piece 6: Side 1

Piece 4 : Side 2

Piece 5 : Side 2

Piece 6 : Side 2

Piece 4 : Side 3

Piece 5 : Side 3

Piece 6 : Side 3

Piece 4 : Side 4

Piece 5 : Side 4

Piece 6 : Side 4

165

167

Roman Strukov

Alvaro Lopez

Nadia Doukhi

Francesca Camilleri

Amalgamma Team 169