Sustainable Hard Machining of AISI 304 Stainless Steel Through TiAlN, AlTiN, and TiAlSiN Coating and Multi-Criteria Decision Making Using Grey Fuzzy Coupled Taguchi Method

High strength, high ductility, low thermal conductivity and high work hardening effects of austenitic stainless steels are the foremost factors that make their machinability difficult. Machining, especially dry machining of such steels, has been one of the most significant challenges for carbide cutting tools. In this research study, TiAlN, AlTiN and TiAlSiN coatings were successfully employed through HiPIMS coating system on cutting tools for dry machining of AISI 304 stainless steel. As-deposited coatings were confirmed through FESEM and XRD analysis. The input process parameters including coating material have been considered for optimizing the multiple objectives such as surface roughness Ra, Rz, tool wear rate and material removal rate. Multi-criteria decision making involving grey fuzzy coupled Taguchi method was adopted to solve the optimization for multiple response characteristics. Analysis of variance was conducted to analyze the contribution percentage of each process parameter. From the results of MCDM-based GFCT, the optimized setting for best output responses was determined as coating: TiAlSiN, cutting speed: 180 m/min, feed rate: 0.1mm/rev and depth of cut: 1.5 mm. Feed rate had significantly contributed about 42.74% on the output measures, followed by coating, depth of cut and cutting speed. The responses were predicted with an accuracy of 96.5% through GFCT technique. Finally, a confirmatory experiment was carried out to support the accuracy of optimal process parameters.