Abstract

Electric Discharge Machining (EDM) is one of the most widely used non-conventional metal cutting processes to manufacture close–tolerance products such as dies and molds. The cost of EDM manufactured part is essentially estimated from the cost of electrode, which is determined by the cost of its raw material and manufacturing process. The present work reports an experimental investigation to study the effects of three different electrode materials, i.e., graphite, copper, and copper–tungsten under the same machining conditions. The pulse current, pulse on–time, spark voltage and depth of cut are considered as control process variables, whereas, surface roughness (SR) and dimensional accuracy in terms of side and bottom overcut (OC) are taken as response characteristics for AISI P20. A full factorial design of experimentation approach is adopted to conduct the machining tests. The results reveal that the copper–tungsten is a better performer for a smooth surface finish and better dimensional accuracy than graphite and copper. This study concludes that the copper–tungsten electrode material is a preferable choice for EDM of AISI P20 to improve the life expectancy of dies and molds.