V.2 Flex Fingers, Swivel Thumb Prosthetic Hand

thingiverse

Update 11/16/17: While an interesting concept, fingers have consistently shown themselves not nearly effective enough - simply too much flex. It is a promising prototype to experiment with and may well lead to even better adaptations, but it falls far short of being truly functional as a prosthetic device. This latest version of the work-in-progress prosthetic hand incorporates flexible fingers, adaptive grip, flexible gauntlet, mesh palm and rotating thumb. The fingers, palm mesh and gauntlet are designed to be printed in flexible filament only. The photos use TPU filament, which is suitable for printing the delicate components needed for a working prosthetic. To scale the fingers, users can adjust the settings before slicing. The current model shows a 125% gauntlet, a 120% palm with two 110% fingers, two 115% fingers and one 120% finger arranged in an approximation of an actual hand. The mesh palm can be printed to match the size of the palm or made larger for added flexibility. Print Settings: Rafts: No Yes Resolution: .3 Infill: Varied The revised .stl files utilize a ball joint attached finger/thumb, giving greater range and flexibility. The fingers have been enlarged at the base and tapered to create an even grasp on objects. To further enhance gripability, the fingertips can be textured. To give users more control, the thumb has been made to swivel in its socket so that it can either oppose or align with the palm. The thumb still functions effectively when the two parts are somewhat parallel. The model includes an updated photo. PLA and TPU were used in different layers: The palm was printed in PLA at 30% infill using support materials to help with construction, with a temperature setting of 200C on the build plate. The fingers were printed horizontally on their sides at 230C using support from the bottom. The model also required varying degrees of infill and TPU print temperature of 17%. For increased stability, the gauntlet is printed standing upright on end at 230C with a brim to prevent movement or distortion. Printers in the wrist region can be removed using a heat gun without creating "angel hair".