Reusable Form for Producing Custom-Fit Grips
The goal of this project was to develop a reusable form that can capture the interior shape of a person’s grip for the purpose of manufacturing custom-fit grips for products such as motorcycles, professional cutlery, golf clubs, and more. This was accomplished with the invention of the phase-cycling form and a corresponding process by which the grip data is digitized, digitally manipulated, and printed into a grip using digital fabrication. Once a phase-cycling form is gripped by the user, it can go from a moldable “liquid” state to a rigid “solid” state instantly on command. The molded form can then be 3D scanned and subsequently reverted to its original state instantly on command. Instant reversibility enables this form to be reshaped many times and without manual resetting, a feat that cannot be accomplished with the current method of using clay or foam. Once a molded phase-cycling form is scanned, the resulting CAD file can be digitally manipulated in terms of shape, surface texture, and color. This CAD file can then be printed using additive manufacturing to produce a grip that perfectly fits the user’s hand.
The physical phenomenon that enables this technology is the jamming phase transition in granular materials. At atmospheric pressure, granular elements collectively behave as a liquid. However, when pressure is applied, they collectively behave as a solid. An example of the jamming phase transition is how you can pour dry sand as if it is a liquid, yet when you step on sand, you don’t sink in like you would in a liquid. This phase transition is caused by the jamming of grains; they lose their ability to slip past each other because they each experience an equal force in all directions. This phenomenon is utilized in a phase-cycling form when the user clasps their hand around a grip-shaped membrane filled with grains, then a vacuum is applied to the grains causing them to transition into a solid in the shape of the interior of the user's grip. Once this molded form is 3D scanned, the vacuum is released and the membrane returns to its original shape, ready to be reused with the grains in the “liquid" state.