Optical surface generation in ultra-precision polishing of freeform

Ultra-precision polishing is an emerging technology for the fabrication of high precision and high quality optical surface of freeform. It is capable of overcoming the shortcomings of other ultra-precision freeform machining technologies, such as the low machining efficiency and non-ferrous materials limitations for ultra-precision raster milling and fast tool servo machining. However, our understanding of the surface generation mechanisms in ultra-precision polishing is far from complete. As a result, an experimental study of the effect of machining strategy on the surface generation in ultra-precision polishing was presented in this paper. A series of polishing experiments had been done. It is interesting to find that the quality of the polished surface heavily relies on a proper selection of process conditions and polishing strategies. The polishing process was not only found to be useful for removing the undesirable machine marks produced by other machining processes but also be able to generate preferred structure texture for functional applications. The results of the study provide an important means for better understanding of the surface generation as well as the strategy for the optimization of the surface quality in ultra-precision polishing of freeform.