Study on Machining Parameters Analysis and Optimization for Material Removal Rate and Surface Roughness During Dry Turning of AZ31B Magnesium Alloy Using Ceramic-Coated Carbide Tool Inserts

This paper presents research findings on the turning of AZ31B magnesium alloy using ceramic-coated tungsten carbide tool inserts in a dry environment. Fifteen experiments were conducted according to the Box–Behnken design (BBD) for the straight turning of AZ31B magnesium alloy to investigate the variations in two important machinability indicators, i.e., material removal rate ‘MRR’ and mean roughness depth ‘R_Z’, with variations in cutting speed ‘C_S’, feed rate ‘f_r’, and depth of cut ‘DoC’. The cutting speed and feed rate had the maximum influence on the mean roughness depth and material removal rate, respectively. To address the challenge of optimizing conflicting machining responses, desirability function analysis (DFA) and grey relational analysis (GRA) were employed to identify the optimal turning parameters for conflicting machinability indicators or responses. These techniques enabled the simultaneous maximization of the material removal rate and the minimization of the mean roughness depth, ensuring an effective balance between productivity and surface quality. The optimal turning conditions—cutting speed of 90 m/min, feed rate of 0.2 mm/rev, and depth of cut of 1.0 mm—yielded the best multiperformance results with an MRR of 18,000 mm³/min and an R_Z of 2.21 µm. Scanning electron microscope (SEM) analysis of the chip and flank surface of the cutting tool insert used in the confirmation tests revealed the formation of band-saw-type continuous chips and tool wear caused by adhesion and abrasion.