DfAM TPU Flip Flop

Flip flops are a surprisingly honest design problem. The sole has to be stiff enough to push off, soft enough not to bruise, and vary continuously along its length without any discrete layers to delaminate. Multi Jet Fusion in TPU is one of the few processes that prints a continuously graded lattice without post-processing.

The midsole is a functionally graded Gyroid — dense at the heel, open at the arch, medium at the ball. The grading is driven by the measured pressure map of a walking gait. It prints overnight in one piece. On sand the grip was better than the injection-moulded pair I was comparing it against, which was the only performance benchmark I had.