Optimized Cutting Process of Flat Wires for Electric Motors with Hairpin Technology

In order to meet the high demand for electric traction motors in the future, it is advantageous in high-wage countries to automate the production process of electric motors as much as possible and at the same time to streamline it. One suitable technology is the hairpin-stator based electric motor. In this paper, the flexible, robot-based cutting process of hairpin windings is presented, which was developed at the Friedrich-Alexander-Univeristät Erlangen-Nürnberg (FAU). A clean and burr-free cut surface is particularly important for the subsequent joining of the wire into the stator in order to ensure a trouble-free process flow. It is also important to produce a clean cut surface, since the hairpins have to be precisely welded together at this point in order to guarantee an appropriate current flow. Within this publication, the hairpin technology and the associated process chain are first introduced and the specific requirements on the cutting geometry are explained. In the second chapter, the various cutting technologies are presented. In the following chapter, the selected cutting geometries are introduced and the development of the (robot-integrated) fixtures is described. Finally, the test execution and evaluation are shown.