Effect of Electrode Surface Profile on Discharge Delay time in Electrical Discharge Machining

In this study, we investigated the discharge delay time of single pulse discharge when the surface of one of the electrodes is rough and that of the other is smooth. Although the delay time of single pulse discharge was shorter when the surfaces were rougher, the delay time was also affected by the surface topography. When the surface of the cathode was rougher than that of anode, the discharge delay time was shorter than that in the reverse case. In addition, in this study, we investigated the discharge delay time of three types of wire electrode used in WEDM. The work functions of the wire materials were measured and the surface electric fields of different surface topographies were analysed. It was found that the discharge delay time of the wire with the highest cutting efficiency was shortest due to the highest surface roughness. The effect of work function on the delay time was found to be insignificant in this work.