Multi-Objective Optimization on Drilling of Titanium Alloy (Ti6Al4V)

Titanium alloys present superior properties like resistance to corrosion, high strength to weight ratio etc, but possess poor machinability. Titanium alloy Ti-6Al-4V is the most commonly used titanium alloy in aerospace and medical device industries. Titanium and its alloys are notorious for their poor thermal properties and are classified as difficult-to-machine materials. Drilling is an important machining process since it is involved in nearly all titanium applications. It is desirable to develop optimized drilling processes for Ti and improve the hole characteristics such as hole diameter, circularity and exit burr of currently available processes. Due to the low machinability of the alloys under study, selecting the machining conditions and parameters is crucial. The range of spindle speed and feed rate, which provide a satisfactory tool life, is very limited. The hole quality (hole diameter and circularity), thrust force, torque and exit burr were evaluated at various spindle speeds, feed rates combinations. The optimized parameter is chosen using the multi-objective weighted sum optimization technique.