Finite Element Simulation Of Ultrasonic Assisted Turning Of Titanium Alloy

Titanium alloys have been widely applied in aerospace engineering fields, and graduallyextended to shipbuilding, metallurgy, chemical industry, light industry, medical andother industrial sectors, with great development potential for high specific strength,good hot strength, corrosion resistance, abundant resources and many other advantages.However, titanium is a difficult to cut materials with poor cutting machining propertiesand thermal conductivity, resulting high temperature in the cutting zone during cutting,and further result is tool failure. Ultrasonic vibration cutting is a periodic reciprocatingmotion with the frequency range of20-50KHz to the workpiece or tool. The ultrasonicvibration turning can improve the turning effect, such as improving machined surfacequality and the accuracy, reducing tool wear and cutting force.A finite elementsimulation model for ultrasonic assisted turning (UAT) of Ti-6Al-4V was developed.Cutting force was predicted during one vibration period. The average simulated cuttingforce was compared with the experimental data with the same cutting parameters. Thesimulated cutting force was well agreed with the experimented one. The averagesimulated cutting force was compared with the experimental data in conventionalturning (CT). The result shows that the average force of ultrasonic assisted turning ismuch smaller than the corresponding force during conventional turning. Cuttingtemperatures for both workpiece and cutting tool were predicted. In order to study theeffect of vibration parameters on machining performance, tool-workpiece contact ratio(TWCR) was defined. Effects of tool vibration frequency, tool vibration amplitude andworkpiece cutting speed on cutting force and cutting temperature were analyzed. It isobserved that both the increase in the tool vibration parameters and the decrease in thecutting speed reduce the TWCR, which in turn reduces both cutting forces and cuttingtemperature. By using the finite element model the appropriate tool vibration frequency,tool vibration amplitude and cutting speed can be obtained.