Experimental Investigation on Flank Wear of the Tool in Ultrasonic Vibration-Assisted Turning of Ti6Al4V Alloy

High cutting temperatures developed during machining of Ti6Al4V alloy diminish the tool life by rapid increase in rate of tool wear. The high cutting temperatures increase the chemical reactivity of the workpiece with tool material and form the localized temperature zones at the vicinity of cutting tool edge. Ultrasonic vibration-assisted turning (UVAT) is an effective cutting technique in which tangential vibrations are provided to the cutting tool. The reduced cutting force and temperature improve the tool life in the UVAT process. In the present study, flank wear of the uncoated carbide cutting tool has been studied in UVAT processes at various cutting speeds (90, 120, and 150 m/min) and ultrasonic powers (80, 90, and 100 %). The flank wear of the tool is measured with a scanning electron microscope, and it is observed that tool wear is low in UVAT compared with the conventional turning (CT) process. Fracture of the cutting edge of the tool is observed in CT because of high compressive stresses with the high cutting temperature, which did not occur in the UVAT process. The growth of average and maximum flank wear with cutting velocity is low in UVAT, whereas rapid growth is observed in the CT process. From the experimental results, tool life improvement is observed in UVAT compared with CT at an average flank wear of 300 mu m; however, this improvement is decreased with an increase in cutting speed in the order of 62, 53.2, and 32 % for 90, 120, and 150 m/min, respectively, at 100 % ultrasonic power. Similarly, tool life is improved with an increase in ultrasonic power in the order of 18, 55, and 62 % for 80, 90, and 100 % ultrasonic power, respectively, at 90 m/min cutting speed.