Optimization of Turning Parameters During Machining of Ti-6Al-4 V Alloy with Surface Textured Tools Under Dry/MQL Environments

In the current study, an attempt was made to optimize the machining parameters during turning of hard-to-machine Ti-6Al-4 V aerospace alloy with different cutting tool conditions like dry turning with untextured and textured tool, minimum quantity lubrication (MQL) turning with textured tool. For generation of textures on the rake face of the cutting tool, femtosecond laser was used. Graphene because of its high thermal conductivity was used as a lubricant with MQL for cooling/lubrication purposes. The turning performance was assessed in terms of flank wear (Vb) and surface roughness (Ra) with various conditions. Taguchi L9 orthogonal array was used for design of experiments, and subsequently, signal-to-noise (S/N) ratio was calculated. It was found that textured tool with MQL improved effectively the Vb as well as Ra as compared to other two conditions. Further, texture tool decreases the tool–chip contact length and therefore increases the machinability of titanium alloy. Signal-to-noise (S/N) ratio as per Taguchi design revealed textured tool with MQL and cutting speed as significant parameters for minimizing flank wear, whereas for reducing Ra feed rate and cutting speed, were most significant parameters. The optimum combination of parameters was cutting speed (80 m/min), feed rate (0.1 mm/rev.), depth of cut (0.5 mm) and textured tool with MQL for flank wear, whereas cutting speed (130 m/min), feed rate (0.1 mm/rev.), depth of cut (1.00 mm) and textured tool with MQL for surface roughness. Taguchi optimized conditions were validated through confirmation experiments and predicted the response factors with less than 5% error. SEM/optical analysis at optimum turning parameters was performed in order to investigate the reduction in flank wear and surface roughness.