DIGITAL DESIGN + FABRICATION SM1, 2016 M3 JOURNAL - Sleeping pod Hoi Man (Priscilla) Kwok
752464 Michelle James - Seminar 1
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Introduction Throughout the entire module 2, focus was put on creating a structure that gives support to users’ neck/ head while they sleep. An idea of a neck ring was therefore used as an initial proposed design which was then turned into a headrest. Skewer sticks are used as the structural material with felt as the outer panels that provide comfort and coverage. Not only did the crossing sticks create geometric shapes for felt to attach on but more importantly a room for user’s arms to go into, giving privacy not only for the head but also the arms to give the sense of protection security.
Yet, the room created for insertion of arms are believed to have created restriction to movement of arms; the fact that the proposed structure has to be laid flat on a level surface when being used also limited the sleeping pose of individuals, which would bring discomfort to certain end-users. In response to the feedback, the initial purpose and idea of the neck ring is revisited and redeveloped. Inspired by the sketch model did in Module 1, the basic shape of a clown ruffle is used and reshaped for both aesthetic and ergonomic.
Hybrid fashion, retrieved from https://au.pinterest.com/
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Design development The new design gives two main improvements, portability and flexibility. The overall shape of the structure is shaped to fit human shoulders and be wearable. It allows users to wear it back to front since it is designed to suit for various sleeping poses.
Since the proposed design is a non-developable surface, it is almost impossible to construct a completely smooth curved shape with panels and tessellation. In order to get the perfect curve and overall flowing profile of the design, I plan to use the method of profile and section to so that it can be achieved by aligning the edges of each section to get the desired profile. However, since panel and fold are assigned and have to be considered in the design, I take into account both comfort and panels to design for pyramids spikes which are attached to the sleeping pod. Each spike was form by folding a flat piece into a 3-dimensional solid with identical panels.
Keeping the idea of allowing user’s arms to be covered to create the sense of security yet avoiding too much restriction on the movement of arms, multiple pyramids are used to achieve this. They are constructed with triangles of felt with stuffing which act as little cushions that provide comfort as well as creating gaps for the arms to place. Since felt is soft and bendable, the spikes of pyramid structures will not cause discomfort and will minimise the restriction to arms’ movement.
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Design development + fabrication of Prototype V.2
Cardboard with a thickness of 1.8mm is chosen in producing the prototype due to its thickness being stiff enough but not too hard to work with. It is cut into four identical strips with dimensions of 25mm x 100mm. 2mm gaps are cut half way through on both sides of each piece for assemblage. Dots are marked on the felt to allow four triangular pieces to be cut and sewed together to form a pyramid spike. In this stage, the way the pyramid is attached to the grid is yet to be determined so hot glue gun is used to join the two elements together. Stuffing is infilled with a piece of square felt glued onto the base to cover up.
This prototype shows one section of the overall sleeping pod. Not only does it present the concept physically but also how the three components, the pyramid spike, the grid, and the inner felt cover, can layer and assemble together to work as a sleeping pod.
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With sufficient stuffing, the inner felt cover (facing up in the photo) will appear to pop out of the grid which creates a tiny square cushion. Having multiple of them laid on the grid can efficiently avoid contact between user’s face and the grid.
Plan
Isometric view
Elevation
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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? In some cases, the processes of fabrication starts from physical to digital which is referred to as “reverse engineering”. Physical prototypes are produced to get a general idea of the design; its geometry can then be scanned with 3-dimensional scanning technologies to turn into a digital version. “Point cloud“, a pattern of points are created from the physical model through scanning and are used to generate profile curves and therefore lofted NURBS surfaces. These processes allow changes to be made and more precise and accurate dimensions and fabrication of the end result.
Contour grid can be created to allow strips of planes to be laser cut and assembled. It also creates hollow sections for stuffing to infill into and sets the rule for felt spikes to be attached.
This diagram show how the machine works for subtractive fabrication technique. It cannot be used to cut into form diagonally.
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Most oftenly a concept design is sketched digitally using CAD (computer-aided design) software and fabricated in the physical form. Digital fabrication techniques can be categorized into 2-dimensional and 3-dimensional fabrication. CNC cutting is a common 2-dimensional fabrication techniques with various cutting technologies such as plasma-arc, laser-beam and water-jet, which involve two-axis motion of the sheet material relative to the cutting head. 3-dimenional fabrication techniques can be subtractive, involving the removal of a specified volume of material from solids using electro-, chemically- or mechanically- reductive processes. However, the range of forms that could be produced is limited as the machine can only move along X-, Y-, and Z-axis. Yet, the addictive fabrication can produce a wide range of forms as it adds layers of materials on top of one another to form a solid work. Formative fabrication however, applies heat or steam onto a material to form it into the desired shape through reshaoing and deformation. To get the flowing shape of my proposed design, I could use either 2D or 3D fabrication techniques. Contour lines can be applied onto the shape in both x and y directions to create a waffle pod, which can then be laser cut into contour planes and assembled. Alternatively, the entire neck ring design can be fabricated 3-dimensionally with either additive technology by layering material vertically to create a solid form, or with formative fabrication to form the material into the desired shape. Subtractive technology cannot be used in this case since the machine can only cut in either x,y, or z-directions which will not be able to create the free flowing form of the proposed design.
Reading applied to design How does the fabrication process and strategy effect your second skin project?
2-D fabrication - waffle pod This fabrication technique seems to be the most suitable to use in achieving the desired outcome. Materials with certain stiffness like MDF or thick cardboards can be laser cut in contour planes and assembled together to form the structural element of the neck ring that give support to user’s head as well as setting the base for felt to lay over. Cotton stuffing can be inserted into the contour grid while the pyramid spikes are to be sewed onto it. However, the felt spikes may not be able to be attached freely onto the structure as designed; they may measured and assembled carefully and precisely in order to fit into the dimensions of the grid with drilled holes so that they can be securely attached. 3-D fabrication - solid form Additive technology, 3D printer for instance, can be used to put layers of material together and construct the structure as a whole with no need for assemblage. In this case however, the pyramid spikes will be tough and stuffing will be very hard to infill into them. The overall weight is also a concern with the use of additive fabrication technique since the material used and the density of the overall structure will directly affect the weight of the structure, making it unwearable and causing inconvenience. Alternatively, formative fabrication technique can be used to form the material into the desire shape. In this case, the structure may have to be altered so it is thinner and less heavy to wear. However, similar to additive fabrication, stuffing cannot be infilled and pyramid spikes can hardly be attached onto the structure, which loses the main purpose of providing comfort.
Instead of having felt spikes in various size and attached randomly onto the structure, the dimensions of each squares of the grid have to be measured precisely in order to work out the size of each spike so they all sit on the grid.
Having the entire sleeping pod printed digitally will result in lack of flexibility and comfort, as well as being heavy to wear.
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Reading Response Wk 7 Digital Fabrications: architectural + material techniques/Lisa Iwamoto. New York: Princeton Architectural Press c2009 Sectioning can effectively elevate the relationship of form with material tectonic. Structural material is cut according to the sections of the form, with are connected together with series of strips that at the same time created a curved surface which has become part of the form itself.
Describe one aspect of the recent shift in the use of digital technology from design to fabrication?
Sectioning is used to take numerous cross sections through a 3-dimentional form. It can turn complex geometries into series of profiles, with the edges of which follow lines of the surface geometry. Sectional ribbing, laminatio/ parallel stacking and waffle-grid construction are commonly used sectioning constructual techniques. It is commonly used in airplane and shipbuilding to make curving surfaces associated with the respective built forms. The bodies are first defined sectionally as a series of structural ribs and cladded with a surface material. Lofting is a method used to determine the shape of the surface panels by building between curved cross-sectional profiles, which the lofted surface can then be unrolled into flat pieces. Sectioning has provided the advantage of perceptually elevating the relationship of form with material tectonic. Greg Lynn asserts that the ‘there are distinct formal and vidual consequences of the use of computer animation... [with] most obvious aesthetic consequence [being] the shift from volumes defined by Cartesian coordinates to topological surfaces defined by U and V vector coordinates.� Sectioning has allowed fluid and digitally driven design to be fabricated with series of contour panels aligning with one and other in order to create a continuous volume. Simple While the design can be derived from a dynamic process, simple planar material can be used for construction. Sheet materials can be cut using two-dimensional computer plots as full-scale template to produce parallel sectioned ribs and construct a curvilinear form.
Sectioning is used in both x and y direction to create a waffle grid with each contour planar surfaces laser cut 2-dimentionally and assembled by hand.
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Computerised three-axis cutting tools such as laser-cutter and CNC routers work from the same polylines to cut two-dimensional materials. While the scale and thickness of materials may vary, the files used to communicate with the pieces of equipment work off the same set of profiles. Chipboard, acrylic and cardboard are some commonly used model-making materials and are easy to use with software such as AutoCAD and Adobe Illustrator.
Reading applied to design Referencing from the lectures and readings, what is the implication of digital fabrication on your design ?
The reason I prefer 2D fabrication is that it allows the structure to be assembled and dissembled freely. The variation of outcomes and effects that are given by different ways of assemblage and composition also create possibilities for new ideas. Unlike 3D fabrication which either subtract or add onto the existing material to create a solid form, the result of 2D fabrication is always relatively light and allows high level of complexity. Taking into account the portability of a sleeping pod and the comfort it has to provide to users, I chose not to use 3D fabrication in the production. My proposed design is first produced digitally using Rhino CAD modelling software. To have it fabricated into a 3D model in 1 to 1 scale, the digital model has to be unrolled into a number of flat segments so that each piece can be 2-dimensionally cut and assembled together. The entire digital fabrication process turn 3D model into 2D, then assembling them to construct a physical 3D model. This is not a linear sequential process but in fact, different steps have to be revisited and changes are to be made to optimize the result. For instance, pieces may not join properly after being cut due to minor error of measurements; changes then have to be made in the digital model precisely to ensure it can be assembled properly.
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Prototype development Since the waffle grid is the main structure in the proposed design that gives support, materials with various properties and thickness are tested to determine the most suitable material in constructing the grid and its junctions. Cardboard - 3mm
Cardboard - 1.8mm
Balsa wood - 3mm
Balsa wood - 1.8mm
Polypropylene - 0.8mm
Cons: it takes more time to cut through due to its thickness, the edge may become loose as the layers of cardboards will separate over time. Pros: has greater stiffness, the outcome is more stable and does not bend easily.
Cons: can be bent and may not be able to maintain the desired shape of the grid. Pros: has enough stiffness to support the structure, rather light weight to be worn w
Cons: Since it cannot be bent, the structure will break completely when force is applied onto it. Pros: does not break as easy as would the 1.8mm balsa wood, it is light in weight and has greater stability due to its thickness
Cons: the material is very brittle and may spilt along the grain. The structure is unstable as the two pieces do not join tightly. Pros: has the lightest weight among all and therefore can be worn and carried easily.
Cons: the edge is rather sharp which may bring discomfort to user; the overall structure has very little rigidity due to the bendability of the material. Pros: transparent in colour for better aesthetic, light weight and can be cut simply by scissors.
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Prototype optimisation
Since the original rhino model was sketched freely without precise measurement, lines are drawn with approximate profile and the overall composition has no balance, the result appears to be of weird composition and profile. Although this irregularity can be used to help emphasis the free flowing shape of the structure and its fluidity, it is not aesthetically appealing and will be harder to fabricate. These irregular contour planes will also create gaps in between one another, which brings to lack of privacy and insecurity as the user’s eyes, the most important part that should be covered while sleeping, will be exposed and distracted.
For better practicality and comfort, human shoulders are carefully measured for precise dimensions of the proposed structure. 20-40 extra millimeters are added on each sides to make the end product suitable for wider range of people, as well as allowing errors in measurements.
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In order to model it on rhino with accurate measurements, a box was drawn with dimension of 40cm x 30cm x 35cm as guidelines. Sub-guidelines are drawn to identify the peak of curves as well as the middle point to ensure that the result is in right proportion and balance. Curved lines are drawn with control point curve to construct a smooth flowing line. Control points are then turned on to adjust the shape to ensure that the result sketch is in the right dimensions. Adding/ deleting control points are also helpful in creating curves with higher/ lower complexity.
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Experiments are also taken on joining cardboard and felt together. Sewing the felt onto the cardboard by laying both of them flat will only join the two by the edge and therefore gives movement to the joint. It provides better flexibility than overlapping the two material and attaching them tightly. Yet, due to the softness of felt, felt pieces cannot be joined in the same way. Instead, thread is sewed through the edge of a piece of felt, with another piece attaching by sewing through the thread of the edge instead of the felt itself. This avoid the two pieces overlapping and will also allow for movement.
Prototype optimisation Before - contours in both x and y directions have interval of 50mm
After - the intervals between contours in x direction are smaller than that of in y direction
The initial rhino model was sectioned in both x and y directions to get the contour panels. They have the same interval of 40cm. However, since the front curve has a steeper surface while the rest of the structure is relatively flat, the contour panels appear to have much larger intervals in the front compare to the rest of the area which leads to two major problems during the fabrication process. Firstly, the overall structure will be relatively fragile since there’s not enough ribs to hold it in shape and therefore less joints to make it stable. This is a structural issue that has to be solved or else it would just collapse. Secondly, not only does the huge difference in size between each spike affect the appearance of the overall structure but more importantly, the entire fabrication process becomes harder as every single grid has different dimensions which require precise measurements and cutting of felt in order to have the spike attached. The interval between each contour planes in x direction is therefore adjusted from 50mm to 20mm so that every grid are similar in size and shape.
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To design for fabrication, the structure was divided in a number of planes by applying contours line in both x and y directions. The contours have an interval of 20mm and 50mm in x and y direction respectively. These contour are then turned into planar surfaces; the intersections of two planes are marked to indicate the positions of cuts. These planar surfaces are then unrolled and expanded. Cut marks are created by first drawing up a rectangle with the width being the thickness of the intended material to ensure the two planes can intersect perfectly, followed by trimming the area within the rectangle to create the cut marks. This step is repeated until cut marks are created for all the intersections. Since felt spikes are to be attached to the grid, holes with a diameter of 0.6mm are created along the edge by first offsetting the shape of individual planes and arraying the circle along the curve. The circles are closely aligned; they are 3mm apart to allow felt to be attached to the grid tighter and neater. As a final step, each planes are etched with a number according to their positions to enable easier assemblage once they are cut.
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Prototype optimisation The waffle grid design is fabricated with 2D laser cutting at a scale of 1:2 to test out on the material and junctions. Cardboard with a thickness of 1mm is used in producing the prototype. It is obvious that the material is too thin that it does not support the composition of the structure which becomes unstable and fragile. Some cuts are too close to the edge, making the planes to break easily. Through assembling parts of the prototype, it shows that cardboard is not an ideal material in fabricating the proposed design. Increasing the thickness of the material can potentially enhance the stiffness and therefore the over stability of the composition, it will however, markedly increase the weight of the structure and making it too heavy to wear. To work out the most ideal material to construct the structural grid, the research and tests on materials are revisited. Realizing that the choice of materials are limited due to the limited types of materials supplied in the fab-lab, I decided that none of them is ideal in producing the grid structure and decided to focus on the properties of the material and how well it can perform rather then whether or not it is supplied and can be fabricated with the fab-lab.
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I decided to use screen board with a thickness of 2mm to construct the structural grid due to its greater stiffness and relatively light weight. Screen board consists of layers of overlapping sheets with semi-gloss finish on both sides. The semi-gloss finish helps in keeping the layers together and reducing the chance of it breaking apart. It allows sharp edges and lines to be laser cut cleanly. Like any other materials, burnt marks are left on the screen board after being laser cut so the pieces have to be spray painted to give it a clean look.
However, since the cut marks made on the rhino model are measured according to the thickness of the material used, every single cut has to be widen up by creating cuts with 2mm width and trimming the excess parts.
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Having thicker material and wider cuts increases the chance of the material breaking, as well as making the entire structure border and more solid, which contradicts with the idea of using 2D laser cut instead of 3D fabrication to increase the fluidity and lightness of the pod. Therefore I decided to expose the waffle grid structure where felt spikes are not necessary. Not only does it effectively reduce the overall weight of the design and increase its portability, but more importantly emphasis the free flowing profile of the design by presenting the sections and reducing the solidity of the structure.
2nd Skin final design
Plan
Isometric view
Elevation
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The sleeping pod is consisted of three main elements, the waffle grid frame, the felt spike and the cushion back. The waffle grid is the structural element that holds all the components together. Holes are cut in the grid so that the spikes and the cushion back can be directly attached to the structure by needle and thread.
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Fabrication Sequence
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Assembly Drawing
Felt is cut into triangular segments and sewed to form an individual pyramid spike, which are then joined together to form the cushion front of the sleeping pod
The cushion backs are directly sewed onto the grid structure through the holes that are cut on the surface of each plane.
The cut marks in both contour planes in x and y direction allow them to intersect with each other and form a waffle grid; they interlock with one another to provide stability and rigidity
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2nd Skin
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Appendix
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75mm 55mm 75mm
45mm 85mm
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85mm
50mm 40mm 50mm
50mm 75mm
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45mm 50mm
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55mm 50mm
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10mm 50mm
55mm
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55mm 70mm
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50mm
The dimensions of each grid is carefully measured to work out the sizes of each individual felt spike. Each piece is cut with 5mm extra in case of error in measurements as well as space for sewing. These excess parts are cut out after all the pieces are sewed together.
Section from the back
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Felt spike and joints
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Elevation and profile
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