Optimization of the Ultrasonic Crimping Process of High-Frequency Litz Wires by Using Process Data Monitoring

From a technological point of view, the contacting process of insulated wires to contact elements is one of the most complex steps in electromechanical engineering. To establish an electrical and mechanical connection of winding ends and contact elements, commonly the wire is stripped before the actual contacting process. However, for high-frequency litz wires, consisting of up to several thousand insulated single wires, the stripping process cannot be carried out in advance. Therefore, processes such as hot crimping or ultrasonic crimping, in which the insulation is thermally removed during the crimping process, are used. The latter is characterized by a significantly lower process energy consumption compared to the hot crimping process. It is therefore most attractive for future applications, but process optimization strategies have hardly been addressed in the literature. Within the scope of this publication, several possibilities of optimizing the process of ultrasonic crimping are investigated by means of systematic process data analysis. For this analysis, directly available data from the control system like the required process energy as well as additionally acquired sensor data, such as the sonotrode oscillation, are taken into account and a variation of process control variables as well as the cable lug clamping is conducted.