A Test Bench Concept and Method for Image-Based Modeling of Geometric Wire Bending Behavior in Needle Winding Processes

The needle winding technology offers the potential to produce high-quality windings for electrical machines. However, realizing this potential requires detailed process knowledge, especially of wire behavior. Therefore, this paper describes the first steps toward detailed data-driven modeling of geometric wire behavior in needle winding processes. We develop a purpose-built test bench that can replicate arbitrary wire bending geometries occurring during regular needle winding. By constraining the wire deformations to a two-dimensional plane, the setup allows the resulting wire shapes, which are otherwise difficult to model and capture, to be recorded with a camera. From the resulting images, a dedicated image processing pipeline extracts detailed spline models of wire bending geometry. Thus, datasets can be recorded which assign the essential influencing factors to mathematical models of the wire bending geometry. Analyses of resulting model behavior show accurate approximation results and confirm the suitability of the developed test bench concept and image processing method for capturing and evaluating wire bending geometries. Thus, this work lays the foundation for an efficient data-driven model of wire bending geometry as a function of wire tensile force and wire exit angles at the needle outlet.