Evaluation of in-line monitoring of micro-forming tribo-systems by consecutive U-bending

Robustness in micro-forming, a critical part of which is system monitoring, is important due to increasing demand for micro-components. In this work, a simulation of a micro-deep drawing tribo-system is applied to investigate the influence of die radius and production speed on process stability and tool wear. Monitoring of force and thermoelectric current are used as tools for wear detection, showing that both signals respond well to wear. The thermoelectric current is more sensitive to slight changes in process conditions and can be recommended as a wear monitoring method in micro-forming over using the force signal. The results of signal monitoring are compared to the surface roughness of formed parts as function of number of strokes, showing a good correlation.