A multi-objective optimization using a combined approach of principal component analysis and TOPSIS during electric discharge machining of H-11 die steel using P/M processed Cu-Cr-Ni metal matrix composite

The present experimental investigation deals with the electric discharge machining of H-11 die steel using metal matrix composite (MMC) as tool electrode. The MMC was prepared using powder metallurgy (P/M) route at a sintering temperature of 800°C. A comparative study has been made using conventional Cu and powder metallurgy (P/M) processed Cu-Cr-Ni MMC as tool electrode. The effect of input parameters like peak current (I_p), pulse-on-time (T_on), duty cycle (DC) and gap voltage (V_g) on response variables like material removal rate (MRR), tool wear rate (TWR), surface roughness (SR) and diametral overcut (DOC) have been analyzed. Multi-objective optimization has been done using a hybrid method of principal component analysis (PCA) and technique for order preference by similarity to ideal solution (TOPSIS) to obtain the optimal set of parameters for copper and Cu-Cr-Ni tool. The optimum parameter setting for copper tool was found to be at I_p=3A, T_on=200_μs, DC=9, V_g=50V and for Cu-Cr-Ni tool was found to be at I_p=6A, T_on=150μs, DC=9, Vg=30V.