Optimization of Machining Parameters in Drilling Ti–6Al–4V Using User’s Preference Rating-Based TOPSIS

Titanium alloys have gained prominence in aerospace and automotive industries due to higher strength to weight ratio and lesser weight. Titanium alloys employed in diverse applications cannot be produced as near net shape components and require holes and other machining processes for structural assembly. Drilling the most conventional machining process is adopted for hole making in titanium alloys. Titanium alloy Ti–6Al–4V is termed as hard to machine materials. In this experimental investigation, drilling experiments are carried out on Ti–6Al–4V with solid carbide drill bits as tool material of 8 mm diameter. Drilling experiments with 16 different trials are carried out by Taguchi’s experimental design. Speed and feed rate are the two input parameters considered ranging from 20 to 50 rpm and 0.05 to 0.2 m/rev. The response attributes measured from experimental investigations are surface roughness, burr thickness, hole diameter and circularity. With an objective of enhancing the drilling process and achieve the desired machining characteristics, machining parameters are optimized based on TOPSIS model. From preference ranking among the alternatives, experimental run 4 is determined as the optimized solution. Optimal machining parameter combinations are obtained at speed 20 rpm and feed 0.2 m/rev.