Theoretical modeling of tool mean temperature during ultrasonically assisted turning

This article summarizes the results of theoretical and experimental studies of average tool temperature in ultrasonic-assisted turning of aerospace aluminum using Al 2 O 3 -coated tools. In theoretical study, thermal modeling of heat source at the tool–work interface and the temperature distribution in the cutting tool are presented. To determine the actual performance, the sticking and slipping tool–chip contact lengths ( l c and l s ) are experimentally measured and then heat source at the tool–work interface is modeled according to the analogy between shear stress distribution and heat source distribution on the rake face. Then, with respect to the kinematics of the process, the cutting velocity model is presented. The velocity model is used to define the heat flux equation and shear strain rate in ultrasonic-assisted turning. Using heat flux function and Johnson–Cook model, the temperature distribution in a semi-infinite rectangular corner, as a function of time and distance from tool tip, is presented. The analysis results are compared with experimental measurements of average cutting temperature from ultrasonic-assisted turning tests on 7075 aluminum using K-type Testo 735 thermocouple. On the other hand, results show that ultrasonic-assisted turning does not necessarily lower the average cutting temperature in all cases. The effectiveness of the technique is highly dependent on the value of vibration amplitude, work velocity, and feed rate. At low feed rates and amplitudes, the average tool temperature for ultrasonic-assisted turning is 60% of the conventional turning value while growing with an increase in feed rate and amplitude.