ELID grinding and simulation of SIC lightweight mirrors

摘要

Lightweight mirrors coated by CVD-SiC can be used as the primary mirrors of infrared space telescopes. This type of mirror is usually designed as regular polygon rib-structures in the rear side. The body of the mirror is so thin that machihing deformation must be considered for achieving high profile accuracy. ELID(Electrolytic in-process dressing)-grinding with superfine diamond wheel is a promising method for finishing lightweight mirrors dut to its higher efficiency and stability. Therefore, we attampt to finish the mirrors with a new processing method combining ELID-grinding and computer simulation. This paper discusses the ELID-grinding characteristics of SiC ceramics through several preliminary experiments. The principle and results of FEM simulation for estimating the deformation of the lightweight mirrors are also addressed.