Nonaxisymmetric aspheric grinding technique for ceramics mirrors

This paper deals with the application of are envelope grinding method (AEGM) for nonaxisymmetric aspheric ceramic mirrors. In this method, grinding point is moved along the wheel profile and the wheel wear is uniformly distributed on the wheel width. In AEGM, however, the cross section of the wheel should be an are profile, and a precise truing technique is needed. Truing accuracy of a resinoid bonded ultra-fine grit diamond wheel was within +/-0.4 mu m. Grinding tests with AEGM demonstrated an excellent grinding characteristic in which wheel life was extended. Form error of the ground SIC ceramics mirror was less than +/-0.8 mu m, and its roughness was R-max = 0.15 mu m.