Multi-objective optimisation in the microturning of cobalt chromium with coated and uncoated tools using the grey relational analysis

Abstract

In this work, the microturning of cobalt chromium has been carried out using coated and uncoated tungsten carbide inserts. The experiments were conducted as per the design of experiments (DoEs) approach using the L9 orthogonal array by varying the spindle speed (S), feed (F) and depth of cut (Dcut) at three levels. The output parameters considered are the material removal rate (MRR), surface roughness (Ra) and tool wear (TW). The significant parameters and their levels were identified using analysis of variance (ANOVA) and response graphs. It is observed that the significant microturning process parameters are found to be different for different tool/workpiece combinations, for achieving a higher MRR, lower Ra and low TW individually. Therefore, a multi-objective optimisation using the grey relational analysis was performed considering MRR, Ra and TW together and the optimum level of input parameters were identified to achieve high MRR, low Ra and low TW together.