High-efficiency and high-quality combined polishing method of zinc selenide crystal (invited)

As an excellent infrared crystal material, zinc selenide crystal is widely used in infrared optical systems. In order to improve the processing quality and processing efficiency of zinc selenide crystal, a method combining magnetorheological polishing (MRF) and traditional numerical control polishing (CCOS) technology was proposed, and the magnetic current of zinc selenide crystal was configured through multiple sets of orthogonal experiments. Change the polishing liquid, carry out magnetorheological polishing on a zinc selenide crystal with a diameter of 50 mm, and then perform traditional numerical control polishing on the surface traces after magnetorheological polishing. The positive pressure is in the range of 0.05-0.1 MPa. Uniform polishing after 30 minites, the surface roughness of the zinc selenide crystal was reduced from 3.832 nm to 1.57 nm, and the roughness was significantly improved. The method effectively improves the processing efficiency of aspheric zinc selenide crystals and improves the surface quality after processing, and has important reference value for aspheric ultra-precision processing of zinc selenide crystals.