Model-based simulation of freeform surface generation in ultra-precision raster milling

Due to the geometrical complexities, the prediction of form accuracy in ultra-precision raster milling of optical freeform surfaces is more difficult than conventional machining. Nowadays, the achievement of submicrometer form accuracy still depends largely on the experience and skills of the machine operators through an expensive trial-and-error approach. In this paper, a model-based simulation system is presented for the prediction of form accuracy in ultra-precision raster milling. The system takes into account the cutting mechanics, cutting strategy and the kinematics of the cutting process. Preliminary experimental work has been done to verify the model and the predicted results agree well with the experimental results. Ultra-precision raster milling is an expensive and complex process, the successful development of the model-based simulation system allows the optimum cutting parameters and cutting strategies to be determined without the need to conduct massive and costly trial-and-error cutting tests.