Suppression Strategy of Micro-waviness error in Ultra-precision Parallel Grinding

Ultra-precision parallel grinding is widely used in the machining of complex optic components with high tolerance and excellent surface finish. However, the micro-waviness raised from the relative motion error of the grinding tool is frequently involved in the grinding process despite the fine dressing and dynamic balance work carried out, which posed a remarkable impact on the surface quality and form accuracy. Therefore, it is essential to investigate the evolution mechanism of the micro-waviness error and determine a relevant strategy to suppress this kind of error. In this paper, a model of the distribution of grinding points corresponding to the relative motion error of the grinding wheel is developed by considering the phase effect. A close relationship is found between the micro-waviness geometry and the distribution of grinding points. This indicates that the phase shift is a significant parameter to determine the waviness pattern, and the uniform distribution of grinding points is beneficial to suppress the micro-waviness in parallel grinding. Finally, an error-suppression strategy is proposed by adjusting the wheel speed to maintain an appropriate phase shift to suppress the micro-waviness error. This work provides a new method to control the micro-waviness and reduce the effect of the waviness error on the surface generation.