Development of a novel rotation-revolution ultraprecision conformal belt grinding based on commercial robot for optical elements

Optical elements with complex profile have been used in many important fields. Their growing market demand has put forward higher requirements for the ultraprecision manufacturing of these optical elements. In this paper, a novel rotation-revolution ultraprecision conformal belt grinding was developed for optical elements based on a commercial robot. Firstly, the rotation-revolution belt grinding device was designed, and the rotation-revolution speed ratio of the grinding device was optimized. Secondly, the pressure model of the rotation-revolution contact area was established based on Hertz contact theory. The posture description and velocity model of the rotation-revolution belt grinding were established as well. And the material removal function of the rotation-revolution belt grinding in any posture was established according to the Preston equation. Thirdly, the effect of eccentricity error on material removal function was analyzed. The parameters of the established removal function were calibrated via the footprint grinding test. Finally, an aspheric optical surface with Sa 9 nm surface roughness and PV 2.7 μm form accuracy was obtained on ZnS material using the designed robot assisted rotation-revolution belt grinding technology.