Process

My approach to this exercise was to first test the material's capabilities and limitations using the available digital fabrication machines. There were two main methods of creating the sealed compartments, namely using the 3D printer's nozzle head to hot-press the 2 sheets of TPU together, and using the heat emitted from the laser cutters to meld the top half onto the bottom piece. In addition to that, we were offered the option of using multiple versions of the material, the main distinction being that the clear one has a homogeneous, glossy texture on either side, while the yellow and dark blue ones have a smooth side for adhesion and a rough side with crosshatched, cloth-like texture for better grip, and to maintain the structural integrity of the piece.

01 | Calibration

The initial couple days were spent calibrating the laser cuttings machines to the appropriate settings for melding and cutting the TPU sheets. My first tests used clear TPU on the GS laser machine, however the results were for the most part unsuccessful as the heat either ended up being too low, creating air gaps and a weak sealing joint, or too high, completely melting the material and penetrating through. Furthermore, the optimal settings kept alternating from time to time depending on the condition of the laser cutters and the material. For example, the laser power needed to be slightly adjusted and increased in the morning during the machine's startup. Another factor that played a huge role on the quality of the seal was the ability of the material to remain flat during the melding process. This proved especially challenging with the clear TPU, as its natural tendency was to deform and wrinkle, particularly on smaller pieces. One keen observation was that the clear TPU needed to rest for a while after melding, allowing the recently heated plastic seams to harden, as to avoid smudging the surface with molten residue or weakening the seal. In comparison, the textured TPU was more forgiving, and was often more consistent in producing a clean seam with little to no streaks or undesirable marks.

02 | Contraction

Following the material testing phase, I was inspired to explore the effect of regulated interruptions across a long surface. These 'phalanges' responded by curling or contracting, varying in outcome based on the proportions, scale and distance between the intervals. Given that soft robotics are concerned with mimicking natural-occurring systems, I tried to use the Fibonacci sequence as the basis for spacing, and curved/ faceted edges to alter the air flow and consequently the level of flexion and extension, reminiscent of hinge joints found in our fingers.

03 | Construction

After observing the behavior of my pieces and those of my peers, I was curious to learn why the objects sometimes 'malfunction' and twist in directions that weren't originally intended. It was here when I realized that using a formless infill like air meant that any fluctuations or inconsistencies in the sealing process greatly affects the outcome. Up to this point, all of us were melding the entire design on one side only, meaning there was more surface tension in that region causing the pieces to contract inwards. My hypothesis was that if I can successfully create a sealed compartment while melding on both sides of the surface, then it would stand to reason that the distinct parts start moving in either direction. This idea guided my design process for the remainder of the week.

04 | Correlation

Identifying the core concept that I wished to explore with this material and its behavior helped me create a rigorous series of tests with controlled parameters that were altered ever so slightly each time. This more scientific approach aided in discovering the properties of each design in relation to one another and also compared to a 'control' piece, effectively discerning the pros and cons of each decision made without overly broadening the scope of exploration.

Latest Prototypes

In the last two prototypes, I tried to increase the scale as well as the complexity of the geometry. This was in an effort to combat the constraint imposed by the size of the pieces so far on the intensity of the contractions and the limits caused by the linear configuration of the geometry.

In the first version, I created an angular zigzag shape with breaks in the corners. The intended effect was that the dual-sided melding would cause the form to compress laterally and extend vertically in either direction. I expected the corners to completely fold, however end result remained somewhat bulbous because the air chambers were too big, denoting that the trapped air wouldn't let the material easily bend in those areas.

The second version of this trial explored a similar idea but within a closed loop. It included two pieces with different positions for the air nozzle to test whether the tension from the inlet and the direction of air flow would change the rate flexion and expansion. After connecting them to a pneumatic pump, the forms twisted in a spiral manner, with the one connected on the outer edge curling slightly upwards.

Insights

Just like in design, this project was a circuitous journey of failure, success and discovery. I found myself always wanting to test different ideas, naturally having a preconceived notion of what will happen, only to be surprised or disappointed by the outcome. Some of the key insights I reached at the end of this course were:

Nozzle | The nozzle shape and size naturally played a role in the amount of air pressure permitted into the structures. Also due to repeated use, the inlet for the nozzles often became points of vulnerability, constantly tearing and ripping, requiring manual repairs using a soldering iron

3D Printing vs. Laser Cutting | While the two methods worked effectively in their own right, the consistency of the results differed slightly. For 3D printing, the heated nozzle of the printer acted as a hot press, melding the two pieces of TPU together. This created clean and air-tight seams that were difficult to separate, however the method took considerably longer. On the other hand, the laser cutters were fast, but the results altered, and more often than not, the seams had imperfections and almost always required manual fixing later. This is because the laser melted the top layer onto the bottom, causing the sheets to buckle and create undesirable air gaps by virtue of an uneven surface

Cutting | While there was not sufficient time in the duration of this project to explore yet another parameter, namely cutting, it could have presented us with a plethora of opportunities for exploration and would've eased the process of fabrication. It could've also allowed for testing larger and more complex shapes that would be more prone to dramatic contractions and transformations

Framing | Given that my focus was on exploring the potential of melding on either side of the artifacts, framing and aligning was a key element that affected the fabrication and production process. It was absolutely crucial that when the piece is flipped it would retain its orientation, and the origin point can be traced back to and aligned for (within a certain frame of error). This reminded me of casting methods, were the preparation of the casts and the mold was often more important than the act of casting itself. This also meant that the Trotec laser machine was more convenient as it had better tools for aligning the surfaces once they are flipped