A transient cutting temperature prediction model for high-speed ultrasonic vibration turning

As a precision machining method, ultrasonic vibration cutting is widely applied for cutting difficult-to-machine materials due to the phenomena of cutting force and the decrease of cutting temperature when coolant is applied. However, the cutting efficiency is limited due to the existence of critical cutting speed of ultrasonic vibration cutting. Therefore, a high-speed ultrasonic vibration cutting (HUVC) method is proposed to realize high-efficiency machining with tool life prolongation and surface quality improvement. The key issue of these advantages is the decrease of cutting temperature within the cutting interfaces. Therefore, it is necessary to figure out the temperature decrease principles when ultrasonic vibration is added. In this paper, a transient cutting temperature prediction model is built to further investigate the mechanism of HUVC. In spite of the average cutting temperature, this model is mainly focused on the transient process. Firstly, the kinematics of HUVC is analyzed, based on which a cutting force model is built. Then, cutting heat is divided into heat generation in cutting duration and heat transfer in noncutting duration, which are then calculated respectively. After calculating the transient cutting heat, cutting temperature in the cutting interfaces is calculated through numeric iteration and integration in the time and space domain. At last, the accuracy of the proposed model is validated by measuring the average cutting temperature through a self-developed tool-workpiece thermocouple. The results demonstrate that the maximum error of this model is no larger than 14 %. Both cutting speed and duty cycle are key factors influencing the increase of cutting temperature in cutting duration and the decrease of it in noncutting duration. In this regard, this model is significant for cutting and vibration parameter setup to obtain an optimal tool life in high-speed machining by restraining the heat generation and enlarging the heat decrease.