1. Bionic Hand – an Overview

Initially, we shall limit ourselves to simpler movements – only a rotation between two adjacent finger parts. There should be enough space without obstacles for moving strings inside the body, and an opportunity to install them (any internal parts) conveniently. Therefore, “a body part” is expected to be composed from two pieces, having axis holes and space shifts for joining different “body parts” altogether. 

The initial shape for modelling fingers are half-cut cylinders. We need parts to overlap partially in order to be fixed one to each other or make a rotating connection.

^{Figure 4. Composition of a finger} 

The space inside fingers is not enough for motors to be fitted inside (or such micro-motors might cost too much), therefore finger parts are moved by pulling strings, and the motors are usually placed in the wrist or the arm part of a bionic hand. 

 ^{Figure 5. Separated parts of a finger}

So, initially, we need to manufacture all necessary parts of a bionic hand. For this, the first step is to create models of these parts. And after that, the obtained models are used to generate instruction files for 3D printers which help us in the manufacturing process.