COMPUTER-CONTROLLED OPTICAL SURFACING WITH ORBITAL TOOL MOTION

Off-axis aspheric optical elements cannot be fabricated using classical techniques. Itek has developed computer-controlled optical surfacing (CCOS) for fabricating aspheric optics. The process slowly moves a polishing or grinding tool assembly (with rapid tool motion) over the workpiece surface. The use of CCOS with orbital tool motion has been put on a scientific basis. Theoretical and experimental removal profiles have been obtained and used. A tool selection process has been developed to provide efficient CCOS error correction. The movement of the tool assembly along a path following the workpiece surface height contours has produced better smoothing and figure error correction. Computer simulations have aided process optimization and predicted excellent results for the use of orbital CCOS polishing.