Cooling mechanism and drill wear of low-frequency axial vibration drilling of titanium alloy

The drilling process of titanium alloy materials is characterized by high cutting temperatures and remarkable chip adhesion to the workpiece, primarily due to their low thermal conductivity and pronounced chemical reactivity. This process results in severe tool wear and reduced tool lifespan. In this work, the heat conduction of a twist drill is analyzed on the basis of the low-frequency axial vibration drilling mechanism of titanium alloy materials. A simulation model is developed to compare the temperature field distribution of the twist drill cutter tooth under two different conditions: vibration drilling and conventional continuous drilling of titanium alloy. Moreover, a comparative analysis of the maximum drilling temperature and tool wear under two different conditions is conducted, thereby elucidating the cooling mechanism and characteristics of tool wear in titanium alloy vibration drilling. Results indicate that vibratory drilling exhibits a more pronounced temperature field gradient in the high-temperature area on the surface of the cutter tooth compared with conventional continuous drilling. Moreover, the average temperature at the outer corner decreased by 25.3 %, and the average temperature at the chisel edge corner decreased by 12.1 %. At the same time, vibratory drilling reduced the tendency of chip clogging. On the basis of the above reasons, vibratory drilling effectively improves the heat exchange conditions of titanium alloy drilling, thus reducing the drilling temperature. Vibratory drilling advantageously enters the normal wear stage later than conventional continuous drilling, and the normal wear stage has a lower VB value and lasts about twice as long as conventional continuous drilling. Therefore, vibratory drilling can slow down the wear and prolong the service life of the drill.