Experimental investigation on electrode wear of array holes machining in micro-EDM

Abstract Electrode wear is crucial for the machining accuracy of array holes in micro-EDM. In order to improve the accuracy and efficiency of array holes machining, the compensation for electrode wear is required. In this study, the effects of essential factors including power modes, open-circuit voltage, capacitance, current limiting resistance, workpiece thickness and electrode diameter on electrode wear were investigated through single factor experiments. It was found that using a TR power supply, lower open circuit voltage could minimize the electrode wear. Electrode wear increases with the increase of open-circuit voltage, workpiece thickness and the number of processed holes, for RC and TC power modes, it decreases firstly and then increases as the capacitance increases. In TC power mode, electrode wear increases with the decrease of current limiting resistance. Moreover, the influencing mechanism of factors on electrode wear were also discussed. In this paper, the functional relations between electrode wear, workpiece thickness and electrode diameter were established, and a compensation strategy for microarray holes machining was proposed to fabricate 5×6 microarray holes, of which the aperture deviation is less than 2 μm and the average diameter is 115 μm. The results of this work are expected to be helpful to provide a basis for the strategy of electrode wear compensation in micro array holes fabrication.