Multi-response optimisation for MRR and Ra in WEDM process of Nimonic-263 super alloy

Nimonic-263 is a nickel-based super alloy with exciting applications. It can retain high hardness and low thermal conductivity even at elevated temperatures. Due to these reasons machining of these alloys using conventional machining is very difficult and therefore wire electrical discharge machining (WEDM) has been selected to machine the material. To get the optimal performance level, the process parameters have to be set carefully. Furthermore, multi-objective optimisation of WEDM process is too difficult as it involves several process parameters. Although there are several multi-response optimisation techniques, industry is faced with a problem of choosing the best technique. The objective of the present work is, therefore, to apply different multi-response optimisation techniques, which are easy to implement and involve less computational effort with a view to recommend best technique. Response surface methodology (RSM) has been used for experimental design. A comparative analysis among the optimisation techniques is carried out. It has been observed that technique for order preferences by similarity to an ideal solution (TOPSIS) is found to be the best among different multi-response optimisations techniques chosen. The total predicted SN ratio values of TOPSIS are 30% more than that of the other methods.