Theoretical and experimental investigation of the effect of the machining process chain on surface generation in ultra-precision fly cutting

Ultra-precision fly cutting (UPFC) is an enabling ultra-precision machining method since it has many advantages such as providing uniform high surface quality, high flexibility necessary for machining freeform or micro-structural surface, etc. However, low machining efficiency is still a problem for UPFC. This paper attempts to increase its machining efficiency by shortening its process chain based on theoretical analysis. A dynamic model considering the whole process chain in UPFC is developed in this study. The dynamic process chain model (DPCM) is basically divided into two parts. The first part is a single UPFC model consisting of geometry parameters and spindle vibration which are primary factors of surface generation. The second part is the preceding surface topography model of the workpiece. An additional coordinate transfer model is developed to combine the above two parts together. Simulation and actual experiments have been conducted to verify the DPCM. The predicted results from the DPCM match the results from the actual machining experiments well. It is found that the parameters are optimized to shorten the process chain in UPFC. In some conditions, the required surface quality is achieved by a single machining step of UPFC directly from traditional turning. On the whole, the process chain model of UPFC provides a feasible way to simulate the dynamic process and observes the change of the surface generation of workpieces when machining parameters change so as to optimize the process chain in UPFC.