Effects of workpiece rotation on machinability during electrical-discharge machining

This work presents a novel rotary (EDM) electrical-discharge machining cutting process for a hard-to-machine cylindrical workpiece. An experimental analysis was carried out on an AISI D2 tool steel with a copper electrode. The effects of machining parameters such as pulsed current, pulse on-time, and workpiece rotation on material removal rate and surface roughness were analyzed. These effects were compared with those of conventional EDM without workpiece rotation. Experimental results indicated that the rotation enhanced the dielectric flow, thus effectively helping flush the debris from the gap between the electrodes. In addition, the material removal rate (MRR) increased with the rotation speed of the workpiece, whereas conventional EDM delivers only half the MRR. Surface roughness improves with increased rotation speed, a phenomenon that is attributed to the reduced recast layer during EDM.