Generation of material removal map for freeform surface polishing with tilted polishing disk

Polishing is one of the key processes for surface finishing. It can achieve mirror-effect on surface by removing the tool masks caused by milling. Since the process is now automated, tilted polishing disk is applied more and more widely, and the prediction of material removal map is vital for polishing trajectory planning to reduce scrap rate and shorten production cycle. This work proposed an improved material removal model of tilted elastic polishing disk by considering the geometric features of contact region, contact pressure, and velocity distribution while polishing. More specifically, based on the FEM simulation results, the contact region and the pressure distribution are discussed in three diverse types according to the geometric features of surface at contact point. The material removal map is then generated by numerical convolution of this model and trajectory planned, with which the issues of material removal, such as over-polishing, under-polishing, and waviness, can be graphically illustrated. To validate the approach, case studies on both planar and freeform surfaces are conducted. Comparative study reveals that the predicted result by the approach agrees with the actual polishing very well. Moreover, according to the generated material removal map, process optimization can be carried out to adjust process parameters, such as feedrate, interval, and step, and hence, mirror-effect surface quality can be achieved.