Study of Surface Roughness in EDM

Electrical discharge machining (EDM) is a widely accepted standard nontraditional machining process in the production of dies and molds. EDM is based on removing material from a workpiece by means of a series of repetitive electrical discharges between an electrode (tool) and a machined part in dielectric medium. The present study is devoted to examine the influences of EDM parameters on surface roughness. The selected EDM parameters were pulsed current (8, 16, and 24 A), pulse time (2, 4, 6, 12, 24, 48, and 100 mu-sec) and pulse pause time (2 and 3 mu-sec). The workpiece material was AISI 1040 steel. Experimental investigation was based on surface roughness of machined workpiece surface and used electrode. It was observed that the combination of low values of pulsed current and pulse time and high-pulse pause time produced a better surface finish quality.