Ex-Lab Journal - Semester 2, 2017

Melbourne School of Design - S2 2017

DIGITAL FURNITURE FABRICATION Alex Morse 521389

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MSD Ex-Lab Tutors: ----------- Adam Markowitz ----------- Randal Kohn ----------- Jas Johnston

Acknowledgements

Experimental Stools Team-mate: ----------- Haoyi Li

MSD FabLab & Workshop Staff

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0.0 Contents

0.0 Contents

9 10 12

1.0 Introduction ----------- 1.1 Journal Overview ----------- 1.2 Introductory Assignment

17 18 22

2.0 Experimental Stool 01 ----------- 2.1 Machine-Specific Focus ----------- 2.2 Final Stool Prototype

27 28 32 36

3.0 Experimental Stool 02 ----------- 3.1 Material-Specific Focus ----------- 3.2 Single-Point Incremental Forming ----------- 3.3 Final Stool Prototype

41 42 44 48 54 68 74 102 112

4.0 Final Furniture Piece ----------- 4.1 Initial Research Interests ----------- 4.2 Material Focus: Concrete ----------- 4.3 Precedent Analysis ----------- 4.4 Casting Method Testing ----------- 4.5 Form Studies ----------- 4.6 Design & Making Process ----------- 4.7 Design Refinement ----------- 4.8 Final Furniture Piece

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5.0 Conclusion ----------- 5.1 Reflection ----------- 5.3 About the Author

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1.0 Introduction ----------- 1.1 Journal Overview ----------- 1.2 Introductory Assignment

1.0 Introduction

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1.1 Journal Overview

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Furniture Design Focus

Research Ambitions

Detail-Oriented Processes

This journal aims to outline the particular research ambitions and physical outcomes achieved through the forms of iterative and process-driven design, allowing incremental prototyping and experimental making to guide the designs and final outcomes for the furniture produced. The concepts of masscustomisation and reusability in the design and fabrication processes were crucial criteria in defining the research streams towards the process-driven methodology of ‘designing the design’, ensuring process would overrule any preconceived final design.

This lead to a concentration on material research and performance, and with my particular interest in concrete shell structures My belief has long been that architecture

and form-found design, processes in material

and architectural design reaches beyond

composition, from aggregate and fibre

that of the built environment we are too

reinforcement, to an understanding in

often focused on at university, and that

form-finding techniques, ensured the design

engagement with furniture design can

was driven by detail-oriented processes

improve our understanding of human space,

in achieving optimised performance in

movement and needs. The opportunity

compressive strength whilst minimising

to explore these design and fabrication

weight.

methodologies within my current degree is something I personally believe is vitally

To conclude, I hope that by being given

important. I have focused much of my

the opportunity to focus on digital furniture

postgraduate study in the area of digital

fabrication through experimental and

design and fabrication, particularly within

process-driven methodologies, will provide

the studios I have completed so far, and

a solid foundation for me to further develop

therefore see digital furniture fabrication as

the skills and confidence I need to pursue

an opportunity to expand my learning, skill

experimental and professional digital design

set and knowledge of fabrication possibilities,

and fabrication methods, both during and

through speculative, experimental and

beyond my studies in architecture and

realised furniture design and making.

design. | 11

1.2 Introductory Assignment

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Making a toolbox

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275

300

426

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(a) 406 440

SIDE ELEVATION 440

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406

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440 406

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to take simple plans of a toolbox (near

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250

The first assignment for the semester was

250

125

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right) and experiment with different joinery techniques, using leftover 15mm furniture

(b)

grade plywood and dowel from the MSD

PLAN

Workshop.

PLAN

250

Given a week to complete this assignment, 25

the key learning outcomes were to quickly get a grasp of the workshop’s tools and to make the toolbox depending on our

300

machines at our disposal, those required

understanding of the accuracy, tolerances

100

making approach, while gaining greater and techniques involved in using the different tools and machines available. A combination of machines were used during the fabrication process, including the table saw (a), hand router (b), and bench drill (c).

250

FRONT ELEVATION

(c) | 13

I wanted to come up with a design that showed no visible fixings or joints, effectively concealing all of these details. This meant ensuring each element of the toolbox was abutting one another, creating ‘grooves’ for each element to slide into, and was neatly capped by the two end pieces.

Despite my best efforts to come up with schematic designs by sketch or on the computer, it quickly proved difficult to translate these into a physical object. It became obvious early on that having a practical understanding of the making process, the tolerances that needed to be allowed for, and the accuracy of each machine (and human) were all crucial elements in the production of the toolbox.

The final outcome was cut tight enough to fit together without glue, nails or screws, which meant the entire design was flatpack and ready for assembly. The shortfall in this design however was its durability, as while the base piece was held securely, the two end pieces would not sufficiently hold the toolbox together for a great period of time our under a given force. The likely improvement would be to increase gluing surface area and introduce a tenon connection joint.

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2.0 Experimental Stool 01 ----------- 2.1 Machine-Specific Focus ----------- 2.2 Final Stool Prototype

2.0 Expreimental

Stool 01

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2.1 Machine-Specific Focus

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The ‘Table Saw’

MSD Machine Workshop

Design & Making Process

This experimental stool assignment (working in pairs) had to be completed in two weeks, solely using the table saw in the MSD machine workshop. This in turn limited our material choices to timbers and ply, whilst also limiting the thicknesses we could cut into or through. Finally, the 3mm blade on the table saw was another consideration to keep in mind when measuring cuts.

Haoyi and I took a conservative approach from an experimental point-of-view, to make sure the structural principles were met in order to achieve a successful outcome for a stool - to be stable and support a person’s weight.

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Exploring the capabilities and limitations

Experimentation into kerfing timber and

We found that whilst developing our stool

of the table saw was the first step to

plywood became our primary focus,

using the table saw, we were cutting each

understanding what we could potentially

reducing the amount of material in sections

piece from the same sheet of plywood.

achieve for our stool. The table saw proved

to enhance and control the bending

Therefore we continued to develop the

to cut accurately and quickly, however

properties of otherwise rigid materials. Tests

design in order for it to come flatpack and

we were limited to straight cuts, grooves

were conducted on hardwood, softwood

easily assembled, using only notches for rigid

and notches into timber and ply, and while

and plywood samples, with plywood proving

joints without the need for additional fixings,

being able to angle the blade for notches

to be the most suitable of the three. Grain

and grooves to add the vertical structural/

or grooves, were still restricted by the 3mm

direction of the continuous top sheet was

load-bearing elements to support the

thickness of the blade that gave a 90 degree

important, along with the spacing-to-kerf-cut

kerfing bends where there were structural

cut.

ratio.

weaknesses.

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2.2 Final Stool Prototype

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Final Design

Design & Process Issues

Areas for Improvement

The final outcome of our stool proved to be quite successful in terms of its structural performance, with both Haoyi and I being able to sit on it, as well as Adam in its final assessment. To achieve this design, any work done digitally beyond the overall form and dimensions really had to be put aside and allow the progress of the form to take place as we cut each piece.

While the stool structurally supported our weight comfortably, its stability posed as a problem as it still had lateral movement and lacked rigidity. This was identified in the minimal vertical surface contact at the notch joints between the vertical legs and the crossbracing elements. Rotating these horizontal cross-braces and increasing the surface contact would help stabilise the stool. | 23

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1. Bend top plywood piece at kerfed corners.

2. Insert cross-bracing elements into notches.

3. Slide shelf piece on top of cross-braces.

4. Insert the vertical dividers/load supports.

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3.0 Experimental

Stool 02

3.0 Experimental Stool 02 ----------- 3.1 Material-Specific Focus ----------- 3.2 Single-Point Incremental Forming ----------- 3.3 Final Stool Prototype

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3.1 Material-Specific Focus

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Aluminium Sheet Metal

Material Properties

This assignment was restricted to a single material - aluminium sheet metal - while being able to use any tool or machine we could to produce an experimental stool.

After initially getting our hands on scrap pieces of 0.6mm thickness, it was clear the sheet metal was easily malleable and rather soft. Multiple folds would weaken the material enough to break it. Moving up to 1.0mm, 1.2mm and 1.6mm thicknesses dramatically improved its strength.

We had the perfect precedent on display, Michael Thorpe’s aluminium stools from the previous semester of ex-lab. We were quickly able to draw inspiration and knowledge on folding and jointing techniques used. | 29

Therefore our initial prototype in the first week of this assignment was to understand the potential modularity of cutting pieces from a sheet of aluminium, along with what types of folds were suitable for improving the strength of the alunimium sheet. It also became very apparent early how sharp the aluminium could get, which added an extra criteria to be met in the design process.

Haoyi designed this first module, which was CNC cut with fold lines scored. The strongest elements of the stool were where the folds effectively ‘increased’ the materials thickness, compared to where folds occurred perpendicular at 90 degree angles that only weakened the material further.

We soon discovered that curving, rather than folding the aluminium sheet was far more effective at giving the metal consistent strength without having to score the material and creating potential weak spots. Our first experiment was on one of the legs of our first prototype, where we curved the leg joint into the stool top, instead of fold it 90 degree (bottom left). The double-curvature created meant the structural load was evenly distributed into the leg over a consistent curve and not stressing the 90 degree fold (that continued to fail as we tested it). From here we progressed to keep working with curving and bending aluminium.

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3.2 Single-Point Incremental Forming

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Lateral Research Stream

CNC Router Application

‘Mass-Customisation’ Concept

While we were designing and trialing modular folded elements for our experimental stool, it was suggested by staff at the FabLab when consulting me on the CNC operations with aluminium sheet that I should give SinglePoint Incremental Forming (SPIF) a try. In all fairness this was just as much of an excuse for them to be able to order in the dapping set (right) to trial this particular CNC milling technique.

However, there was great potential to what single-point incremental forming can do, in terms of being able to take a planar surface and generate curvature for strength and stability.

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The method requires the aluminium sheet to be elevated off the bed and the CNC tool bit to be calibrated. It effectively runs a very similar tool-pathing operation to that of a standard subtractive job (e.g. milling timber or foam), yet only moves at a speed of 500mm/min without any rotation of the tool bit. It also requires a greasy lubricant to be applied to the surface in order to minimise friction and create heat.

We decided to attempt (very quickly) a stool top to be incrementally formed with the FabLab’s CNC router, a job that if successful would have taken 7.5 hours to complete.

Unfortunately, due to the straight vertical increments in the tool-pathing setup, the aluminium ripped before it was able to continue inwards. | 35

3.3 Final Stool Prototype

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Final Design

Design & Process Issues

Areas for Improvement

With the single-point incremental forming experiments not being successful at the time of submission, taking a far more manual approach in order to achieve the desired outcome for the stool became a valuable learning curve.

With the aim to achieve greater strength through curvature in the aluminium rather than simple folds, we acquired a greater understanding of the behavior of the material, through identifying its strengths and weaknesses.

Despite not achieving many things we ambitiously set out to do in only two weeks, we still successfully fabricated a stool structural enough to sit on (right)! | 37

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1. Rolling the aluminium legs over dowel.

2. Drilling pilot holes for pop-rivets.

3. Pop-riveting the legs to the stool top.

One of four legs assembled.

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4.0 Final Furniture Piece

4.0 Final Furniture Piece ----------- 4.1 Initial Research Interests ----------- 4.2 Material Focus: Concrete ----------- 4.3 Precedent Analysis ----------- 4.4 Casting Method Testing ----------- 4.5 Form Studies ----------- 4.6 Design & Making Process ----------- 4.7 Design Refinement ----------- 4.8 Final Furniture Piece

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4.1 Initial Research Interests

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Structural Optimisation

Mass Customisation

While completing my masters, I have

The structural design strategies I hope to

Mass customisation is the concept of

developed particular interests in both

incorporate and develop for my furniture

customising products at mass-production

structural design optimisation and mass

piece include form-finding, such as reverse

efficiencies, where the customisation

customisation, after completing both Alberto

catenary methods (hanging chain model),

aspect has little to no interference on the

Pugnale and Paul Loh’s design studios. I saw

hyperbolic paraboloids (ruled surfaces) and

cost or speed of production. While I have

the opportunity to continue these research

minimal surface generation (soap bubbles),

previously studied the application of this at

streams through furniture design, and to be

all of which inherently provide structural

a larger architectural scale, this concept is

able to work at a 1:1 scale.

performance through their geometric

particularly relevant to furniture design due

composition. Secondly, these strategies allow

to the scale and variety of furniture making

Ex Lab provided the perfect platform to

for minimal material to be used due to their

processes that already exist.

establish and develop process driven

structural design, providing the opportunity

methodologies through iterative design to

for far lighter furniture as part of the design

I hope to be able to develop a process that

effectively test these research interests side-

consideration.

includes both of these strategies as the driver

by-side. I hope to achieve a furniture design

behind my design thinking and decision-

that integrates both structural optimisation

Not only being able to design, but test and

making when producing my final furniture

through form and minimal material, as well as

replicate these strategies on a physical 1:1

piece.

have the capability to be readily and easily

scale will allow me to better understand and

customisable within the one making process.

hopefully develop new structurally optimised processes for design. | 43

4.2 Material Focus: Concrete

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Concrete Composition

Aggregates & Additives

After considering each of the research streams I wished to explore further, the material I was going to work with not only had to be developable enough to form some rather complex geometric forms, but also be adaptable enough to introduce customisation within a single process.

Therefore, concrete was chosen due to its flexibility during the casting process while wet, and its structural performance once hardened. I was quick to then determine which mixtures of concrete, in terms of aggregate size and type, water to cement ratios, and chemical additives provided the best flowability and workability when casting without compromising strength. Tests were done with all of the above variants to determine a final recipe I would work with for the remainder of the semester (p.47). | 45

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Weight measurements of the concrete

Accurate ratios of water/additives

Thorough stirring for consistency

Demoulding for finish texture

Concrete/grout with fine sand aggregate

Accurate water ratio for flowability

PVA-based admixture for strength

Plasticiser for improved workability

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4.3 Precedent Analysis

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Design Inspiration

Architectural Forms

Concrete Use in Furniture

(1)

Precedent research took place into both architectural and furniture projects that utilised concrete as the main or only material.

I had previously come across the work of Heinz Isler, a Swiss architect renowned for his concrete shell structures, and instantly took design inspiration from the likes of the

(2)

Deitingen Service Station (1) and the Gips Union Laboratory and Research Facility (2) which both implement structurally optimised forms to create beautiful geometries both structurally and materially efficient. My search for furniture using the same design methodology led me to Foster & Partners’ Arc table (3), a lightweight, fibre-reinforced concrete table base replicating minimal surface stretched fabric forms. However, it is also the finish to this table that got me really excited about the beauty in concrete!

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(1)

After having found precedent projects that inspired the kind of design I was aiming to achieve, further research went into projects that used unique methods of casting to find either structural or minimal forms.

(2)

The MASS IIII stool (4) by Janwillem Van Maele was developed while studying at De Hogeschool West-Vaanderen, and introduced me to the casting method of fabric-formed concrete. He used an unusual casting method, which once the fabric template was sewn (1), it was hung upsidedown and dry-packed with the concrete mixture (2), before being soaked with water to allow the concrete to harden (3). Once demoulded (which must’ve involved tearing away the fabric), a really consistent finish to

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the concrete was created.

(4)

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(3)

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(1) Another project I came across in my research that utilised a fabric formwork was the MARS Pavilion (3) by Form Found Design introduced me to the method of fabric-formed concrete. This project in particular used an elastic fabric sewn into a triangulated form to create unique structural elements for the pavilion (2). Each of these were fixed at one point with the other two moved into place with robotic arms (3), stretching the fabric so the tensile strength of the form held its shape when filled from the top with concrete. The subtle variation this casting method allowed lends itself the concept of mass customisation I am trying to incorporate into my own design process. It did beg the question in terms of reusability which I hadn’t previously considered, as the fabric would potentially peel off if it wasn’t infilled or sewn.

(2)

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4.4 Casting Method Testing

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Infill Fabric Casting

Testing Reusability

Post-Formed Stretch Casting

Inspiration from the precedent research initiated my own casting processes using stretched fabric, with my first test ‘jig’ replicating the casting method of the MARS Pavilion (right). Before I had even done a cast, I quickly realised that once the fabric has been sewn into a particular shape, the flexibility in its customisation was quite limited as the stretch holding the form tight had to pull in a particular direction.

I was also interested in whether the fabric would stick to the concrete once it was poured and had hardened. Fortunately, the fabric could peel from the concrete, however the form made it rather difficult to do without breaking the cast. This was also only possible due to the fact the cast was kept straight. | 55

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After the initial experiments concluded that the fabric would not get stuck to the concrete (and proved to be reusable once cleaned), I was then interested in designing a formwork that would begin to replicate forms more similar to that of the Arc Table. I also wanted to move away from the sewing that restricted variability, to allow a single piece of fabric to be stretched into different forms, varying what the casting system could do.

I developed what I called a variable formwork ‘machine’, that clamped down a flat sheet of lycra and point-stretched it upwards from underneath using upsidedown quick-grip clamps. The concrete would be poured onto the lycra and the lycra stretched at the points predetermined to the cast.

This method instantly failed, as the points stretching up the lycra began to split the wet concrete and gravity did the rest in pulling it back towards the edge. The lycra did provide some resistance to slumping however, but not enough to hold the concrete form together.

It also became noticeable the extent at which the lycra could stretch, and the added impact the weight of the concrete would have. The first attempt of having four points pushing through the lycra close to the clamped edge heavily restricted the lycra stretching potential.

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The following attempts using this system took into account the previous failures.

Firstly, only a single centre push object was stretched through the lycra, increasing the distance from the clamped edge to allow greater stretch and height. It became apparent that there was a direct correlation between the height at which the push object could stretch the lycra to, and its proximity to the fixed clamped edge. Secondly, the issue of the slumping concrete was only minorly resolved, with some manual hand trowling pushing the concrete back up the surface as it was stretched to maintain a consistent surface layer. This resulted in incrementally stretching the lycra in small intervals to ensure the concrete didn’t begin to slump and allow 62 |

the lycra to provide some resistance.

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4.5 Form Studies

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Physical Sketch Models

Digital Simulation

Form Refinement

With the physical fabric casting providing a better understanding of the types of forms that could be developed with the lycra, I started producing quick sketch models using some lycra offcuts to tests the forms pointstretching it could generate. And once three or more points were stretch through, the form was able to be flipped to give a sense of how this form and structure was potentially going to develop into a piece of furniture.

It became apparent that the number of variations that could be generated were endless, almost to the point of it being meaningless. This for me determined that the actual design challenge was in identifying the constraints and parameters that would define the form, and strategically control them based on input requirements. | 69

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Determining inputs (boundary edge, number and position of stretch points, desired height) would be applied to a set of constraints (point-to-point and point-to edge ratios based on desired height) in order to define the parameters of the formwork system. Therefore I developed a parametric script in Grasshopper 3D to simulate the physical properties I was producing with the ‘machine’, in the hope of establishing a live feedback loop between quick form generation digitally and the physical performance of the stretched lycra, both with and without the weight of the concrete casting. The more accurately I could feed data into the parametric model, the more accurately I could begin to simulate the physical stretching method. | 73

4.6 Design & Making Process

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‘Designing the Design’

Process Issues

Achieving Consistency

Refinement of the concrete casting process took place iteratively as the variable formwork casting ‘machine’ slowly evolved as each cast was poured. This began by adding a top layer of lycra to the casting process, in order to try and achieve a consistent finish on both sides of the concrete form (p.77). This meant that there would no longer be any manual trowling on the topside of the concrete as it stretched upwards. In order to space the lycra layers, a PVC pipe fitting was placed in the cast with the intent of maintaining the cast’s thickness.

Additionally, a thinner lycra was tested with the aim of achieving greater height in the form. While an initial stretch test without concrete proved successful (right), ultimately the concrete did not cast as desired due to insufficient tensile strength in the lycra. | 75

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Concrete poured as previously done

Second layer of lycra placed on top

Everything clamped down at the edge

Considerable failure with thinner lycra

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After the failure of the previous cast, the following iteration of the machine used the thicker lycra from the initial casts, as the aim was to first achieve a consistent topside finish prior to resolving height issues. It was clear at this stage that attempts to resolve too much too quickly would likely cause more failures than successes.

This next cast produced some very interesting results, with majority of the form retaining a consistent thickness and finish to both sides.

The issue of resolving the slumping (above) of the concrete now provided the greatest challenge. It was unclear at this stage whether the slump was due to insufficient tension in the lycra layers, or simply a miscalculation in the volume of concrete required for that form.

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This attempt used a much thinner edge profile of only 6mm MDF to space the two lycra layers, compared to the 15mm plywood previously used. The aim was to test if the concrete would still have structural integrity at this thickness, while hoping to resolve the slumping of the previous prototype by reduce the weight of the concrete relative to the surface area of the lycra. Additionally, four points were stretched to understand how the concrete would cast in the section of lycra suspended at the centre of the form.

This cast proved to be most successful in achieving a consistent finish and thickness, however resolving the edge details remained a challenge. The PVC pipe offcuts were not originally intended to remain in the cast, however provided a unique opportunity to resolve the feet detail. | 83

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The next evolution of the design process involved a significant amount of mechanical upgrades to the machine, beginning with replacing the quick-grip clamps as the push objects. Two main reasons being that the uneven jolting motion of ‘pumping up’ the clamps meant there was little accuracy in measuring height, with the second being that stretching to a given height was not always achievable given one’s own strength.

Therefore, threaded rods that fed down through two tee nuts to hold them aligned.

Finally, 3D printed components capped the locked nut ends, one a turning handle at the bottom and the other a protective cap that ensured the lycra stretched over the top wouldn’t catch and begin to rotate with the threaded rod.

Continuing with the idea of embedding feet into the cast concrete, copper pipe fittings were purchased and turned on the wood lathe (they get bloody hot!) to achieve a clean finish at the desired height.

The casting method remained the same for consistency purposes, however the material was again changed back to the thinner lycra that had previously failed. The reason for this being that I knew it would reach the desired height of 400mm, but by only casting a 6mm thickness instead of 15mm, hoped the reduced weight would allow it to hold its form. After demoulding the cast, it was a huge relief to see that the concrete had cast all the way to the top, although disappointingly the copper piece was too smooth to bond with the concrete.

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As the last prototype cast had for the first time achieve the desired height there were some more finer finishing details that were left to be accomplished. These were 1) the consistency across the surface (not allowing pockets to slump), 2) embedding the feet during the cast, and 3) achieving a smooth and level edge detail. This prototype cast was therefore poured with an even wetter mix of concrete, to the point where it was hard to contain within the boundaries of the cast. It did however produce by far the best finish in terms of consistency and cover right down to the edge of the formwork.

Unfortunately, the copper pipe was too sharp for the lycra and ripped it once the formwork had been stretched to its full height.

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Small modification again occurred to the formwork machine this iteration, firstly with the addition of small metal eyelets (or grommets apparently) at the material’s edge to allow it to be hooked onto the formwork template and easily removed again for cleaning.

This was previously done using a staple gun which obviously tore the lycra and made it extremely hard to remove again. A redesign of the edge condition to the formwork meant that the concrete would be able to cast onto a flat horizontal plane, with the hope of creating a neat level edge finish. Meanwhile, a rounded-off 3D printed cap to sit over the sharp copper piece at the stretch point ensured the lycra wouldn’t be torn again this time round.

Finally, to challenge the previous prototype cast in terms of finish quality, this final prototype was poured again with a really wet mix. I was concerned that using too much water would compromise its strength due to its relative thickness, but this was something worth testing regardless. What was rather interesting to observe was the way in which the excess water bled through the lycra formwork after it had been stretched into place, hinting that excess water may just be the key to allowing the concrete to remain flowable enough before the stretching allows it to bleed away. The final result produced something interesting. The bottom two-thirds had the most refined finish to date, with a smooth, flat edge. Unfortunately, it must’ve been a lack of concrete volume that caused it not to fill to the top.

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4.7 Design

Refinement

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Final Machine Design

Full-Scale Casting

With the parametric simulation running along side the physical casting process, a form was decided on to pursue for the final furniture piece. This meant scaling up the size and operation of the machine and in turn the volume and weight of concrete it must support. It wa also extremely important that the machine be constructed accurately, in order for casting consistency, the formwork to remain stable and level, as well as structurally support the amounts of concrete cast on top of it.

A final design of the machine was developed in Rhino and sent for CNC milling at the FabLab. The strategy involved a simple design that interlocked for ease of assembly, but also disassembly, just in case any particular part had to be altered. | 103

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With the machine framework structure and horizontal plates CNC milled and assembled, the finer details of the machine had to be installed. These included the 3D printed threaded rod caps and centre-clamp aligning pin, along with the eyelets and screws to ensure an even stretch of the lycra over the edge profile. The edge profile also had to be sanded and coated to ensure the concrete would not get stuck in this delicate groove, or break during demoulding. Finally, the decision was made to double up the bottom layer of lycra on the formwork, as I was concerned about the increased weight it was going to have to support.

With all parts in place and assembled, and trial runs conducted to monitor the stretch of the fabric prior to casting, the machine and process was ready for its first concrete cast. The first cast o the machine used approximately 25kg of mixed concrete and evenly poured across the flat surface. The initial part of the process went well, with the concrete in place and the second layer of lycra clamped down. Additional lycra strips were stretched across the valley points of the top lycra layer to keep these points in contact with the concrete. Unfortunately, after stretching each of the threaded rods to a height of 300mm, with only a matter of 50100mm to go, one of the points tore through both bottom layers of the lycra, causing it to collapse. The splitting and cracking of the concrete during the stretching process may also have been due the additional time it took to mix and then pour the increased amount of concrete.

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Learning from the initial test cast with the machine, final efforts were focused on ensuring the lycra didn’t rip, and the consistency and fluidity of the concrete mixture was increased. A new batch of 3D printed caps were produced with increased tolerance to ensure there was no potential for them to rip or damage the lycra when being stretched, along with applying WD-40 and petroleum jelly to all moving parts to better lubricate the machine. The concrete mixture was measured far more accurately, with increased amounts of water, along with an Air Entrainment Agent (additive) that improved workability of the concrete.

Yet despite these improvements, the lycra formwork still failed, along with the cast not reaching the desired height. Where the concrete was cast up to, the cracking and splitting was almost completed eliminated and a relatively consistent finish achieved, meaning the mixture itself was done to the correct ratios and properties.

The key conclusions to take away from this was that the compromise made to reduce the thickness of the lycra to allow for the increase in stretch and height of the cast, meant that proportionately the weight and volume of the concrete across the surface area had to also be significantly reduced.

Attempting to cast a 15mm consistency simply wasn’t going to work.

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4.8 Final Furniture Piece

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Final Design

Successes & Failures

The design and submission of my concrete

imperfections where the fabric did not

coffee table did not turn out as I had hoped

remain in contact with the surface or the

for. This began with the fabric tearing at one

mixture was inconsistent.

of the stretch points which meant that my four-legged coffee table became three, and

There were a few positives to take out of this

despite my best efforts to salvage the cast at

however, with some success in creating the

the time to create a level section as if it were

concrete edge for the glass to sit flush with,

somewhat intentional, simply didn’t compare

despite parts breaking when it was pulled out

to the design I was intending to achieve.

of the mould. And secondly, the finish to the embedded plywood disk, that was originally

The actual cast itself also didn’t perform as I

only intended to clamp the centre point

had hoped it would, despite my calculations

of the formwork, had a surprisingly smooth

and measurements to pour the correct

finish, inspiring the potential for alternative

amount of concrete, create a lower-density

feature centre pieces. Overall, an extremely

flowable concrete mixture, strengthen the

disappointing submission in comparison to

lycra fabric, and refine the mechanics of the

what I had hoped to achieve, however I am

casting ‘machine’. Finally, the quality of the

more determined than ever to continue this

concrete finish didn’t achieve the level I had

project and get it right!

hoped for, with many holes and | 113

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5.0 Conclusion

5.0 Conclusion ----------- 5.1 Reflection ----------- 5.2 A Bit About Me

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5.1 Reflection

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Expectations vs Outcomes

Achievements

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Future Speculations

Upon reflection of how I feel the semester

simulate the fabric stretch and form my

went from an experimental fabrication

variable formwork would produce, allowing

point-of-view, it was without a doubt

me to more accurately measure quantities

successful (despite the disappointment with

for each cast. However, where I had

my final submission piece). The reason for

previously believed that it was insufficient

this being that focusing on the process of

quantity that was the cause of imperfections

making, through experiment and iteration,

or casts not filling to the top, it actually came

rather than being driven by a particular

down to a weight-to-area/volume ratio

outcome, provided far greater satisfaction

that caused this. The fabric itself, despite

when the process did work, and more often

being stretched to a fairly rigid tensile state,

than not presented new and unexpected

would still only be able to hold a certain

opportunities along the way.

amount of weight across its surface while maintaining its form. Therefore I realised that

Working with concrete for the majority of the

I was attempting to cast the concrete at a

semester certainly provided its challenges.

far too generous thickness of 15mm+ for my

A material of two extremes - when I got it

final piece which is what caused the failure in

right it would produce a beautiful raw finish

the fabric and the inability to cast to the full

with considerable structural performance,

height of the formwork, where much thinner

Going into Ex-Lab this semester, I knew the

but when I got it wrong it would fail

casts of under 10mm had successfully done

workload expectation was going to be high,

comprehensively. This fine line was incredibly

so. If I had have pushed to achieve a more

and it certainly lived up to that expectation.

hard to manage throughout the semester,

daring and delicate thickness as I scaled up

The main reason for this was the intense rate

and while trying to develop a casting system

my process from prototype to final form, the

at which we simply had to produce stuff,

that was both reusable and customisable,

final piece may just have been a successful

whether it was likely to work or not. For myself

meant it was incredibly hard to produce

one.

personally, this was the greatest hurdle in

consistency in the casting I was doing while

progressing through the subject as it is not

maintaining durability in the casting process.

I am determined to get this right and

in my nature to throw myself into something

The system of casting itself I believe got to

have the process producing beautiful

without first thinking through every possible

a point that was beginning to provide that

concrete furniture, as it is not the variable

scenario or option in order to be confident

consistency, particularly the fabric texture

or customisable aspects that have failed.

in what I’d do next. However, I quickly came

and forms being produced. However, more

With these still being the drivers behind the

to realise how important it was to get out

diligence and control needed to be taken

entire process, I will continue to develop

of ‘hypothetical land’ (as Adam would tell

when mixing the concrete for casting. This

my casting method and formwork system

me) and simply just make/cast/break/etc.

was often the final stage in the process that

over the coming weeks, as not reaching the

Any form of speculation really had to be put

was rushed or poorly thought through.

level of quality and finish I had hoped to for

aside no matter how logical it may have

submission has only motivated me more to

seemed at the time to continue to learn

Towards the end of the semester I was able

through making and experimenting.

to develop a parametric script that would

get this right!

TO BE CONTINUED... | 121

5.2 About the Author

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Alex Morse

Melbourne School of Design

I am currently studying the Master of Architecture degree at The University of Melbourne, after completing a Bachelor of Environments with a major in Architecture.

Throughout my short career at university and in professional practice, I have developed a particular interest in digital and parametric design, with a keen eye for detail and fascination with technology.

Working as a digital fabrication technician at the University’s FabLab (Digital Fabrication Workshop) has inspired a greater passion for integrated prototyping and making into my design processes using advanced CNC and CAM technologies.

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Thank you.

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