Precision Micro-EDM Milling of 3D Cavities by Incorporating In-situ Pulse Monitoring

Abstract

The tool wear in micro-EDM milling can be measured off-line intermittently to adjust the wear compensation factor and to guarantee the machining accuracy. However during milling of complex 3D cavities, the off-line tool wear compensation has to be done more often which negatively affects the duration of the overall machining cycle. A combined off-line and in-line adaptive tool wear compensation method is proposed and experimentally validated for a more efficient machining approach. The method minimizes the off-line compensation operations by maximizing the in-line compensation via real-time pulse counting to predict the tool wear. The factors affecting the performance of this combined method are also addressed, where the change of tool path pattern being the most important one. It can effectively be detected by in-situ pulse frequency monitoring and generally requires a change from in-line to off-line compensation to maintain the desired machining accuracy.