Validation of on-machine microfeatures volume measurement using micro EDM milling tool electrode as touch probe

In micro electrical discharge milling, process parameters have to be empirically calibrated in order to achieve high precision machining; to this end, on-machine measurement of the material removed is of paramount importance. The capability of electrical discharge machines in detecting electrical contacts between the electrodes can be exploited to perform dimensional measurements, using the tool electrode similarly to the touch probe in a coordinate measuring machine. In this work an investigation of the accuracy of the on-the-machine volume measurements in a micro electrical discharge milling setup is carried out and an evaluation of the error affecting on-machine measurements is provided.