Sensory Perception & Interaction Research Group

Designers, makers, and artists prototype physical products by iteratively ideating, modeling, and realizing them in a fast, exploratory manner. A popular method of bringing 3D designs to life is through casting. Casting is the process of pouring a material into a mold, such that once the material sets, the target object is created. Currently, the process of turning a digital design into a tangible product can be difficult. One reason for this is that building the mold - for example by 3D printing it - can take hours, slowing down the prototyping process. This can be particularly true when prototyping molds for casting interactive (sensate and actuated) or geometrically complex (curvy) objects. To this end, we developed two mold-making techniques intended to facilitate different, complementary needs for rapid prototyping. The first technique we introduce is Silicone I/O, a making method based on Computer Numerical Control (CNC) that enables the molding of sensate, actuated silicone devices. This method uses stacked laser-cut slices of wood bound together with molten wax in order to create cheap, accessible, one-time-use molds that are quick and easy to assemble. The Silicone I/O devices are pneumatically actuated using air channels created through lost-wax casting, and made sensate by mixing carbon fibre with silicone. The second technique that we describe is FoldMold, which allows curvy molds to be rapidly built out of paper and wax. This approach is based on “unfolding” a 3D object, cutting the 2D layout, and using papercraft techniques to reassemble the mold. Beyond the physical challenges of rapid mold-making, digitally designing mold patterns from 3D objects poses a bottleneck in the design process. We contribute the FoldMold Blender Add-on, a computational tool that turns 3D positives into CNC-ready papercraft mold patterns. This thesis contributes within two different broad approaches to increasing increasing speed in mold prototyping. The first method is by creating flat, laser-cuttable mold patterns, significantly speeding up the actual mold creation process. The second method is by automating mold design, off-loading much of the tedious design work to a computer software that can help a maker design a mold very quickly.