Abstract
This report deals with the development of a numerically controlled (NC) aspherical lens grinding and polishing machine and the manufacturing tests of aspherical surfaces by means of this machine. An NC fine grinding machine of a vertical lathe type is constructed. Optical surface is ground by diamond wheel whose horizontal and vertical positions can be determined by NC in unit of 1 μm and 1/6 μm respectively. This machine, however, reveals somewhat unsatisfactory surface performance, so that a new type of polishing tool named "small tool of variable eccentricity with 2 axes" is developed. This tool has single polishing pad and 2 axes for pad rotation and revolution. Pad size, rotation speed and the distance between 2 axes are determined experimentally. Polishing pressure which is given by compressed air is also variable and the pad can be moved up and down with a constant pressure to the work surface. For the experimental verification, the figuring of paraboloid is executed. The inverse Ronchi test shows that the central part of the initial sphere (200 mm diameter, 1200 mm radius) is turned into the paraboloid, and the validity of this small tool is confirmed.
