Experimental investigation and fuzzy TOPSIS optimisation of Ti6Al4V finish milling

Ti6A14V is a well-known ‘Difficult to Cut’ material in the aerospace industry. Ti6Al4V shows strain hardening, poor thermal conductivity and chemical reactivity at elevated temperatures, which implies low machinability. This work presents an experimental investigation of 3D finish milling of Ti6Al4V material by Taguchi design of experiments, having L25 array. The considered process parameters are cutting speed, feed, depth of cut, tool type, coolant type and computer aided manufacturing strategy. The experimentation is conducted on the 3D finish milling process, and the performance in terms of tool life, tool wear and surface integrity were recorded. The fuzzy technique for order of preference by similarity to ideal solution, a multiple-criteria decision-making tool, was applied on experimental responses. The yielded optimum results are derived at minimum cutting speed, moderate depth of cut, feed rate per tooth and collaboration under high concentrated wet lubrication using a PVD-TiAlN cutting tool driven by streamline computer aided manufacturing strategy. In addition, analysis of variance confirms the influential process parameter contribution on the respective performance. Finally, optimised process parameters were applied for the gear bracket finish milling through streamline CAM strategy, which results in minimum flank and crater wear with an average surface roughness of 0.17 microns.