Research on a large depth-to-diameter ratio ultra-precision aspheric grinding system

In the work reported in this paper, the factors affecting the surface roughness and profiles accuracy of machined large depth-to-diameter ratio aspheric surfaces in the ultra-precision grinding process were analyzed theoretically. An ultra-precision aspheric grinding system was then designed and manufactured. An aerostatic form was adopted to build the spindle of the workpiece, the transverse guideway, the longitudinal guideway and the spindle of the grinder in this system. The following specification was achieved: the turning accuracy of the spindle of the workpiece is 0.05 μm, the highest rotational speed of the grinder is 80,000rpm and its turning accuracy is 0.1 μm, the resolution of the linear displacement of the transverse and longitudinal guideway is 4.9 nm, and the adjusting accuracy of the precise adjusting mechanism is 0.1 μm. Finally, numerous ultra-precision grinding experiments were carried out on this grinding system. Some optical aspheric parts, with a profile accuracy of 0.3 μm and a surface roughness of less than 0.01 μm, were obtained.