Discharge current shape control method and experiment in wire EDM

In order to study the effect of discharge current shape on surface roughness and processing speed in wire EDM process, a pulse power generator of adjustable current shape was developed. Based on half-bridge topology of pulse power generator, the various current shapes were generated by the control method of single-arm intermittent turn-on power tubes, regulating the gap discharge current raising time and falling time. The comparison experiment between rectangular waveform and triangular waveform indicated that the processing speed of rectangular waveform was high and the surface roughness of triangular waveform was good. To avoid the contradiction between the processing speed and surface roughness, the narrow triangular pulse combination waveform was investigated. According to the rectangular waveform and triangular waveform machining features, a multiple cutting strategy was discussed that rectangular waveform was used to rough cutting and the triangular waveform was used to trim cutting. The experiment shows that the cutting strategy can obtain a good processing effect.