Motion Characteristics of Discharge Channel in WEDM

Abstract

ABSTRACT Discharge channel motion characteristics are one of the focuses of electrical discharge machining (EDM) mechanism research. Based on single pulse discharge experiments, discharge channel motion laws of wire-cut EDM (WEDM) under different electrical parameters were researched. Results show that discharge channel motion speeds are highest at the beginning of the discharge, then drop sharply, and finally enter a relatively stable state, due to the current density change, pressure difference change between the inside and outside of the discharge channel, and the electrode wire shape itself. When discharge time lasts from 0.5 μs to 5 μs, the discharge channel average moving speed drops by about 60%, and when discharge time lasts about 15–25 μs, the discharge channel diameter expands to the maximum. Continuous machining experiment reveals that the variation laws of both cutting efficiency and a single discharge crater surface area with electrical parameters are consistent, that is, the motion laws of a single pulse discharge channel can microcosmically reveal cutting efficiency variation laws in WEDM macroscopically. Improving cutting efficiency only by increasing pulse energy (especially pulse width) is difficult. In high-speed WEDM (HSWEDM) process, the pulse width exceeding 75 μs is proved to have little effect on cutting efficiency improvement.