A Response Surface Methodology to Optimize Multiple Discharge Step Parameters for Sinking Electrical Discharge Machining

Conventional die-sinking electrical discharge machining (EDM) employs a single electrode operating under constant discharge conditions. We explored a two-electrode scenario, in which roughing and finishing were coupled. We developed a multiple discharge step (MDS) method that uses three discharge depths. The discharge current is highest in step 1 and lowest in step 3. Response surface methodology (RSM) was employed to optimize the discharge conditions. Experimentally, the MDS method combined with RSM decreased electrode edge wear and surface roughness compared to the conventional method, with no increase in the average discharge current.