Enhancing Prosthetic Dexterity by Integrating Multi-Material Printing and Design

5000 hand amputations occur annually in the US. With the average cost of a prosthetic hand currently over $10,000, many amputees are left without access to a functional prosthetic hand. 3D printing technology offers a solution to lower the cost of prosthetic hands. However, current affordable 3D-printed prosthetic hands are fragile, complex, and lacking realistic dexterity. The goal of this research is to develop a next-generation 3D-printed prosthetic hand with advanced dexterity, light weight, durability and affordability. Thermoplastic Polyurethane (TPU) is a 3D-printable plastic with elastic properties. Through the application of TPU as a material for finger joints, the number of components can be reduced while dexterity is increased. This study involved the production of a prototype prosthetic hand using a multi-material design with rigid Polylactic Acid (PLA) finger segments and TPU finger joints. The resulting prototype features only 26 parts and is capable of several grip types. It uses a design inspired by the skeletal structure of the human hand, with individual metacarpal sections attached to a carpal hub. Future development of this concept will yield further improvements by increasing the range of motion of each digit, testing with real patients, and enhancing hand performance with the use of electric motors.