Executive Summary : | The fundamental objective of material science and engineering is to select appropriate methods and manufacturing techniques to optimize the cost of the component. The brisk progress of manufacturing industry helps indevelopingsuitable methods to machine advanced materials suchas titanium and its alloys. Increased strength at elevated temperatures in addition to exceptionalcorrosion resistance and biocompatibility have made titanium a sought-after metal employed in manufacturing, petroleum industry, automobile, aerospace and medical field. Titanium Grade 5 (Ti-6Al-4V) finds broader application in the aerospace industry due to its superiorproperties. Ti-6Al-4V alloy is utilised for its high temperature strength, fracture toughness, anti-corrosion and weldability. This alloy is used either separately or in combination with other materials in fuselage, undercarriage and engine parts of an aircraft. Machining of Titanium Grade 5 (Ti-6Al-4V) has thrown lot of challenges to the shop floor machinists and designers. Because of its mechanical and thermal characteristics, the commonly prevalent issues in machining are higher deviation in the dimension of the work part, greater surface roughness values, and higher levels of cutting tool wear / shorter tool life, excessive amount of chatter and vibrations, enormous amount of heat generation during cutting. Complications in machining of titanium can be attributed to various factors like poor thermal conductivity, high rates of strain hardening, hot hardness and greater chemical affinity towards tool material. Combination of increased cutting temperature, high heat retaining capacity and low thermal conductivity will result in development of high thermal stresses at the cutting zone leading to blunting of the cutting edge of the tool. This in turn generates more heat, and the cycle persists resulting in complete tool failure. Also, high chemical reactivity of the chips so formed leads to welding at the tool tip and cutting edge resulting in tool failure. The current project explores the effectivenessof various coolant delivery approaches in identifying and reducing the dimensional deviation/ change while milling Ti-6Al-4V. Dimensional accuracies play a major role while this grade of Titanium is used in aerospace (airframe, turbine compressor blades, landing gear, exhaust ducts and engine parts) and astronautical (support structure for thrust reverser) applications. Also, variations in cutting forces, surface roughness, chip breakability, cutting tool wear will be investigated/studied to ensure improved machinability of Ti-6Al-4V. |