Multi objective optimization of EDM process parameters using fuzzy TOPSIS method

With the increasing demands of high surface finish, development of newer hardest material and machining of complex shape geometries, conventional machining process are now being replaced by non-traditional machining processes. Electrical discharge machining (EDM) is one of the non-traditional machining processes which are based on thermoelectric energy between the work piece and an electrode. A pulse discharge between the work piece and the electrode occurs in a small gap removes the unwanted material from the work piece material through melting and vaporizing. The electrode and the work piece must have electrical conductivity to generate the spark. Surface roughnesses (SR), higher material removal rate (MRR) and lower tool wear rate (TWR) are of crucial importance in the field of machining processes. This paper summarizes the fuzzy TOPSIS technique, in order to optimize the cutting parameters in EDM for stainless steel of S304 grade. The objective of optimization is to attain the minimum tool wear rate, higher material removal rate and the best surface quality simultaneously. In this present study L₉ orthogonal array has been used and the input parameters selected for optimization are flow rate of dielectric, peak current, pulse on time, pulse off time. For each experiment MRR, TWR and SR are measured. By using multi objective optimization technique, the optimal value for MRR, TWR and SR is obtained by using fuzzy TOPSIS techniques.