DIGITAL DESIGN + FABRICATION SM1, 2016 M3 JOURNAL - A space for confessions
Danika Pandinata, Phoebe Goh Shiyi, Pingrong Chen, Yu Chia Lim (848706), (813480), (837679), (816571) Luca Lana + #2
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Introduction
Based on our personal space concept of having a moving confession room, the rhino model produced portrayed a single person wearing the designed piece but after the feedback from the M2 presentation we have decided to split the design into two so that the wearers will meet and connect to carry out the function intended. We were also concerned about the way the structure can be supported on the body, as well as its flexibility, ability to maintain its shape and its durability. There was also a need for anchor points on the body to ensure that the structure holds on its own.
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Design development
These are sketches produced after the feedback, with major changes being the listener’s and speaker’s pieces being separate from each other and connected when desired. To increase the comfort of the wearer, more headroom is provided. Supports were also considered in this sketch as the design extends down to rest on the shoulders.
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Design development + fabrication of Prototype V.2
Our first laser-cut prototype was produced and transparent polypropolene was chosen as a material due to its flexibility. As it negates the desired effect of blocking vision due to it’s opacity, we attempted to cover the polypropolene with a reflective foil card.
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The rhino model is produced from refined design sketches after receiving feedback from M2, such as the separate head and mouth part, the increased headroom for the head piece and the anchoring of the structure on the body.
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Reading Response Wk 6 Architecture in the Digital Age - Design + Manufacturing/ Branko Kolarevic, Spon Press, London c2003
Briefly outline the various digital fabrication processes. Explain how you use digital fabrication in your design? The types of design processes: 1. SUBTRACTIVE FABRICATION Removing specified volume from solids. (Laser Cutting, CNC Milling). Downside: limitation of 3 axial miling, limited range of form, burnt marks from machines. 2. ADDITIVE FABRICATION Adding materials in layers to create the shape. (Selective Laser Sintering, Stereolithography, 3D Printing, Laminated Object Manufacture, Fused Deposition Modelling, Multi -jet Manufacture). Downside: Limited size, costly equipment, lengthy production time. 3. FORMATIVE FABRICATION Create shapes through reshaping or deformatons such as heat or steam. Downside: School doesn’t have this. Our system is panel and fold. We need to cut out the panels and play with the folds so we decided to use the subtractive fabrication, laser cutting to help us cut out the panels in our models. We decided on laser cutting because we are more familiar with it and CNC milling is more expensive. We need to pay for the toolpathing and the cutting.
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Reading applied to design How does the fabrication process and strategy effect your second skin project? Potential effect as whole without so much 1:1 scale model prototypes “Reverse engineering” Seeing how it might looks like in the 3D model first for how it might work when human is involved and can change as much as we want until we are satisfied and make it out. Cutting out- “The fact that complex geometries are precisely described as NURBS curve and surfaces, and thus, computationally possible also means that theiir construction is attainable by means of CNC fabrication processes.” The use of this system helps us to cut weird and complex shape that we had unrolled from the our model. Shape are all weird and luckily the use of fabrication process will help us to cut the weird shapes accurately and nicely. Saving time and effort - “Digital fabrication can offers productive opportunities within schedule and budget frameworks” This is true as we experienced it in the production of the headpiece part. The aluminium foil can’t be laser cut because its made out of paper so we had to cut it manually for each panels. The problem with this is that it takes so much time, effort and human resource to do it. What can be done with laser cutting within approximately 1 day using machine took us 2 days to cut with 4 human. There’s also less mess generated.
Prototype module
Module tested out in human form
Weird shapes when unrolled, and many.
Neatly cleanly cut & less messy
Manual cut, not so clean & messy
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Reading Response Wk 7 Digital Fabrications: architectural + material techniques/Lisa Iwamoto. New York: Princeton Architectural Press c2009
Describe one aspect of the recent shift in the use of digital technology from design to fabrication? With the help of computer technology, forming tessellations of varying sizes and forms is much easier (pg 36). This is evident in our design process, as we used Rhino to form the desired effects. We started out with a plane, and created points in a grid format. Through these points, panelling tools were used to form a tessellation across the whole design. Rhino also enabled us to play around with varying thickness of the tessellation and from there, we could experiment with the different effects created. With the form, we are able to reverse engineer the design and create individual pieces to be laser cut. This is done through Unrolling. These individual pieces are then joined together with metal brads to create the final form.
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Reading applied to design Referencing from the lectures and readings, what is the implication of digital fabrication on your design ?
The digital fabrication processes allow designer a better and more efficient way of making models. By having parametric software such as Grasshopper we now can designer a more complex geometric form such as Federation Square. We no longer have to made the model from 2D drawing instead we can go on fabrication from 3D models straight.
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Prototype development
One of the major concerns of this design is the connections between the various pieces. Rivets and different lengths and orientations of metal brads have been tested for their strength, flexibility and buildability. We have decided on metal brads of 19mm and orientated to be perpendicular to the running strips. This reduces the resistance produced by the brads against the shape when it is connected in parallel to the pieces.
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To connect the headpiece and the mouthpiece, we have tested on magnets on the polypropolene, but the magnets (above) were not strong enough to withstand the tension between the strips. Velcro was chosen instead due to its strength. We hid the velcro strip on the inside of the headpiece (right above) and create a loop using velcro on the mouthpiece (right centre). The loop is then attached to the velcro strip to create the connection of the mouthpiece and headpiece (right below).
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Prototype optimisation
The idea of a confession is mainly around anonimity. With anonimity, the confessor will be able to comfortably express his or her feelings.
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Our attempt with the effect of anonimity is through using visual effects to confuse onlookers.
We tested with holographic card and reflective foil card, and we though that the reflective foil card produced stronger visual effects. The reflection of light can be bedazzling especially if the wearer is in conditions which has bright lights.
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Prototype optimisation
Our initial module that is repeated throughout the design was created by two curves curving inwards (left above). After repeating the module (left below) we then fabricate by dividing the module into strips in one direction from the rhino unrolling process. However, we modified the curves so that they face outwards (right above) as this allows the place of holes onto the rhino model (right below), which enables the fabrication process to be easier and faster as the location of the holes are marked. As the unrolled strips do not have holes at regular intervals due to the strips conforming to the planar surface, this enables us to know where the joints are located.
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1 2
3 4 5
6 The design in rhino is produced by first creating a surface (image 1, 2) and then a network surface grid (image 3)which can be tweaked and adjusted to modify the surface (image). After obtaining the desired shape, a bounding grid is created around the surface (5). These two grids allow the panelling tools to fit the modules onto the curves of the surface (6).
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Prototype optimisation
Our second prototype was the mouthpiece laser-cut on a 0.38mm thick transparent polypropolene. Due to the inherent qualities of the material used (transparent polypropolene is less stiff, more flexible) and the thinness of the material, the mouthpiece failed to produce the shape modelled in the rhino design as it lacked the stiffness for it to hold its shape. Another problem is that the laser cut produced obvious burnt marks on the transparent prolypropolene.
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For our final model we decided to use black polypropolene in 0.6mm thickness instead. And the results as below showed that this material is more able to hold its shape, due to its thickness and the fact that black polypropolene is stiffer and less flexible than transparent polypropolene.
To optimise the laser cutting process and waste less material, we have arranged the unrolled strips of the rhino model in a way such that we can fit as many as possible within one piece of material.
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2nd Skin final design
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The final design produced is as shown in the photos above (left: headpiece, right: mouthpiece), in its natural state.
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Fabrication Sequence
1. Pieces of laser-cut polypropolene were collected and labelled according the rhino model to enable assembly.
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2. For the headpiece which is covered in foil card, contact adhesive is sprayed on both sides of the polypropolene which will be sandwiched between the foil card
3. The glued strips are cut out by hand and relabelled. The holes are also punched through again through the foil card.
4. The metal brad is pierced through the slit at the joints of the strips
5. It is then pressed flat against the polypropolene, perpendicular to the length of the strips.
6. The brads are connecting the strips at alternating holes for each strip to create the openings.
For the mouthpiece, only steps 1, 4, 5 and 6 are carried out as it is not covered with the silver foil card.
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Assembly Drawing
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1. After collecting pieces from laser cut, arrange according to numbers labelled on rhino file. 2. Connect using brads at alternating points, e.g. holes 1, 3, 5, 7, 9 for the first strip, holes 2, 4, 6, 8, 10 for the second strip, and consecutively. (see enlarged diagram) 3. Repeat steps 1-2 for the mouthpiece. 4. Place velcro loop on mouthpiece and velcro strip on headpiece to enable connection between the two pieces.
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2nd Skin
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