Comparative study on the application of GRA, PSI and hybrid PSI-GRA techniques for optimising turning parameters in multi-criteria problems

The optimum turning parameters help to justify the investment in machine tools for manufacturing industries. However, solving optimisation models to achieve optimum turning parameters in multi-criteria environment is complex leading to the application of multi-criteria decision-making techniques. This paper compares three multi-criteria decision-making techniques in determining optimum turning process parameters namely spindle speed, feed rate and depth of cut. The performance criteria are material removal rate, consumed electrical energy and tool wear rate. Example data for turning process were obtained from other studies while the analyses for multi-criteria decision-making were performed using grey relational analysis (GRA), preference selection index (PSI) and hybrid PSI-GRA techniques. The results show that, hybrid PSI-GRA is the most effective technique taking advantage of the strengths of both GRA and PSI techniques. The optimum process parameters are spindle speed N = 355 rpm, feed rate f = 0.05 mm/rev and depth of cut d = 1.5 mm with associated material removal rate MRR = 5846.11 mm3/min; consumed electrical energy CEE = 0.0871 kWh; and tool wear rate TWR = 0.0415 μm/min. These parameters are considered efficient and can help to achieve higher performance of turning operations including lower cost, higher productivity and higher product quality.