To realize high efficiency, low/no damage and high precision machining of tungsten carbide used for lens mold, a high frequency ultrasonic vibration cutting system was developed at first. Then, tungsten carbide was precisely machined with a polycrystalline diamond (PCD) tool assisted by the self-developed high frequency ultrasonic vibration cutting system. Tool wear mechanism was investigated in ductile regime machining of tungsten carbide. The cutter back-off phenomenon in the process was analyzed. The subsequent experimental results of ultra-precision machining with a single crystal diamond tool showed that: under the condition of high frequency ultrasonic vibration cutting, nano-scale surface roughness can be obtained by the diamond tool with smaller tip radius and no defects like those of ground surface were found on the machined surface. Tool wear mechanisms of the single crystal diamond tool are mainly abrasive wear and micro-chipping. To solve the problem, a method of inclined ultrasonic vibration cutting with negative rake angle was put forward according to force analysis, which can further reduce tool wear and roughness of the machined surface. The investigation was important to high efficiency and quality ultra-precision machining of tungsten carbide.

With the increasing market demand for optical complex surface parts, the application of multi-axis ultra-precision single-point diamond turning is increasing. A tool path generation method is very important to decrease manufacturing time, enhance surface quality, and reduce cost. Compared with the tool path generation of the traditional multi-axis milling, that of the ultra-precision single-point diamond turning requires higher calculation accuracy and efficiency. This paper reviews the tool path generation of ultra-precision diamond turning, considering several key issues: cutter location (CL) points calculation, the topological form of tool path, interpolation mode, and G code optimization.