Investigation of effects of different cooling systems on tool life and surface roughness in machining of Ti-6Al-4V alloy

Titanium alloys are excellent material due to their superior properties. However, titanium alloys are generally regarded as difficult to machine materials due to their low thermal conductivity, which leads to high temperatures on tool-chip and tool-workpiece interfaces. By eliminating the difficulties in the machining of this material, the desired quality and standards, low-cost production can be achieved. In this study, the effect of cutting conditions on turning Ti-6Al-4V alloy at high speeds (125m/min, 250m/min and 350m/min) was investigated. Four different cutting conditions (Dry, conventional coolant, Cryogenic and Minimum quantity lubrication) were taken into consideration. Damage types occurring on the tool surface were determined and an appropriate cutting condition was determined in terms of tool life. According to the results obtained, the increasing cutting speed causes the coolant to lose its coolant/lubricant effect. The dominated damage mechanisms in cutting tools; abrasiv, adhesion and diffusion. The tool life at a cutting speed of 250 m/min was found to be lower than 350 m/min. In terms of surface roughness, it is more appropriate to use conventional cutting fluid at low cutting speeds. However, at high cutting speeds, the cutting condition does not have a decisive effect on surface quality.