Machinability of Ti6Al4V in High Speed Micro Turning Under Dry Condition

Ti6Al4V alloy is increasingly being used in the biomedical, aerospace, and automotive applications due to its outstanding corrosion resistance and increased specific strength. Due to high chemical reactivity, lower thermal conductivity and low elastic modulus the machinability of Ti6Al4V is very poor causing high tool wear as well as surface roughness. Micro turning is a technology to fabricate miniaturize cylindrical components; however, the poor material removal rate promotes the requirement of high speed micro turning. In this work semi high speed micro turning operation in dry condition have been performed on work piece of 3 mm diameter with constant feed rate (2 µm/rev), constant depth of cut (50 µm) and two levels of cutting speeds (94.2 m/min, 141.3 m/min). Two different combinations of cutting speed have been used because during high speed operation rapid spark was generated as the heat completely accumulated in the chip tool interface carried out by the chips and the tendency of spark generation is increased which might damage the machine tool. Investigations have been performed on the topography of the machined surface, the burr formation and tool wear. Surface roughness of 0.592 μm have been achieved during the experiment at lower cutting speed however when the value of cutting speed increases the surface roughness value increased due to rapid heat accumulation. Additionally, rapid crater and flank wear on cutting tool were investigated. The tendency of formation of exit burr width has been increased at higher cutting speed. All of these phenomena are expediting the requirements of cooling technologies during high speed micro turning of Ti6Al4V.