IMMA Hand

IMMA hand is a low-cost 3D printed anthropomorphic prosthetic hand, with 6 degrees of freedom actuated by tendons: flexion in each finger and flexion and abduction in the thumb. Different materials are used in the hand to obtain the proper stiffness and friction coefficient in each area in order to improve the grasping ability: PLA SOFT-Flexible^® is used for the palm and phalanges, NinjaFlex^® is used for the elastic joints and FilaFlex^® is used for inserts located in the finger pads and some areas of the palm. Four nylon fishing lines (diameter 0.50 mm) are used as tendons for flexing the fingers and two more for flexing and abducting the thumb, with an appropriate routing through the phalanges. A knot is used to attach the tendon to the distal phalanges, being this knot hidden below the inserts used in the distal phalanges.

Note that this hand is just a prototype and can not be used as a prosthesis directly, it needs a socket and a control system. It could be completed and customised for use as a wrist driven prosthesis.

Partially inspired by: Flexy-Hand (joints), ADA (axes of the thumb and fingers orientation), K1 (fingers orientation), Tact and Dextrus hand (flexion and abduction movements of the thumb actuated separately). The dimensions of the hand fingers and palm were selected to be between 50th percentiles of human male and female hands, based on data obtained by the research group Biomecánica y Ergonomía (Universitat Jaume I).

To obtain the files for printing the hand prototype please fill in this form and we will send you the files by e-mail.