The present invention relates to an apparatus for polishing or grinding optical surfaces and particularly to a device for either grinding or polishing cylindrical mirrors of the type used in, for example, X-ray telescopes.
Cylindrical grinding or polishing heretofore involved devices for turning the cylindrical workpiece about its longitudinal axis. As the work piece is turned, a pad, usually mounted on an arm, is positioned so it is in contact with the inner surface of the cylindrical workpiece. A slurry on the surface acts to either grind or polish the surface as the workpiece is turned.
The polisher described above is operated so that the pad is urged against a portion of the inner surface of the cylindrical workpiece. As the workpiece is rotated about its longitudinal axis, the portion of the surface contacted by the pad is either polished or ground depending on the slurry being used at the time. After a period of time, the pad is positioned to contact another area of the cylindrical surface. Operating the roller polisher in this manner, however, produces ridges on the cylindrical surface caused by either the overlapping or the failure to overlap areas being polished or ground when the pad position is changed from one position to the next. To overcome the problem of the ridges produced by operating the polisher in the above-described manner, the pad can be continually reciprocated in a direction parallel to the cylindrical workpiece axis. This approach, while largely eliminating the problem of creating ridges on the cylindrical surface, does not readily lend itself to precise grinding and polishing of the surface.