Abstract: In order to realize ductile-regime machining for tungsten carbide as optical die material,it was machined using Cubic Boron Nitride (CBN) tools under the assistance of laser heating and ultrasonic vibration.The cutting force variation characteristics in the three cutting modes,such as common cutting,ultrasonic elliptical vibration cutting,laser assisted and ultrasonic elliptical vibration composite cutting,are analyzed and the model of cutting force of tungsten carbide in laser assisted and ultrasonic elliptical vibration composite cutting is established.The experiments were carried out on an ultra-precision lathe assisted by YAG laser equipment and self-developed ultrasonic vibration device.The influences of cutting parameters,such as cutting speed and cutting depth,on cutting force were studied through a series of contrast experiments.The theoretical model and experimental results show that,because of the softening of the workpiece material and the interrupted cutting,the composite assistance of laser and ultrasonic vibration can largely reduce the cutting force while machinability of tungsten carbide can be remarkably improved.Furthermore,precision machining of tungsten carbide can be realized under certain optimized technological parameters.

Key words: tungsten carbide, CBN tools, cutting force, laser assisted and ultrasonic elliptical vibration composite cutting