Evaluation of surface roughness and MRR of EN18 steel tool in EDM process

Abstract

Electrical discharge machining also known as EDM has been proven as an alternative process for machining complex and intricate shapes from the conductive ceramic composition. It is generally used for machining of very tough and brittle electrically conducting material. In this experiment EN18 steel is used as work piece and copper is used as tool. EN series is a popular steel tool. There are three input variable parameters used which are current, pulse time and duty cycle. Taguchi method is used to create L9 orthogonal array of input variables. MRR and Surface Roughness is found out and the effects of the input variables on this characteristics are studies in this experiment. The EDM machine used in this experiment is ELECTRONICA -ELECTRAPLUS PS 50ZNC (die sinking type) EDM. After the results have studied it is found out that current is most significant value followed by pulse time and duty cycle is least significant for both MRR and SR. both MRR and SR increased nonlinearly with the increases in current. As pulse time increases MRR decreases slightly and with increase in duty cycle it increases insignificantly. But SR first increases with increases in pulse time but after 500ìs it decreases. For duty cycle also SR increases up to 65% then started decreasing.