Abstract: A novel approach for discharge machining with semiconductor electrode is presented in order to produce multi-channel discharge in electrical discharge machining (EDM) for overcoming the current limitations of discharge machining theory. Firstly, it is experimentally proved that the multi-channel discharge could be formed by processing metal with semiconductor silicon as an electrode. Secondly, the equivalent circuit model of a single-channel discharge with a semiconductor electrode is developed. The results show that a silicon electrode is not an equipotential material in the discharge machining. Additionally, an experiment regarding the potential distribution of electrode is conducted as well. The findings confirm that the formation of the multi-channel discharge is due to the high voltage at areas far from the discharge point where the breakdown discharge can be simultaneously formed. Eventually, a single-pulse discharge experiment and EDM processing experiments are conducted using semiconductor silicon electrodes. In the single-pulse discharge experiment, 15 discharge channels are simultaneously formed in a single-pulse discharge. And the outcomes reveal that multi-channel discharge with silicon electrode could efficiently disperse the discharge energy, while the depth and diameter of each erosion crater are significantly decreased in comparison with metal electrodes. Moreover, under the same discharge parameters, compared with steel electrodes, the surface roughness value of EDM with silicon electrodes decreased by 71.7%.

Key words: electrical discharge machining, semiconductor electrode, multi-channel discharge, discharge equivalent circuit, potential distribution of electrode