A comparative study: surface characteristics of CVD-SiC ground with cast iron bond diamond wheel

Abstract

Efficient precision machining of CVD-SiC (chemical vapor deposited silicon carbide) reflection mirrors in extremely low surface roughness and high form accuracy is greatly demanded by advanced industrial fields. The existing lapping methods have a great difficulty in satisfying these demands. Some researchers proposed ductile mode grinding technology, but it inevitably required a very expensive grinding machine, and its grinding process with such fine abrasive wheel was usually unstable. Dr. H. Ohmori put forward a new idea of application of ELID-grinding to ultraprecision grinding of CVD-SiC mirrors. The method had a potential to solve the above problem. In this paper, the precision grinding of CVD-SiC was performed by two kinds of methods. One is the ELID grinding; the other is the ordinary grinding with the saw-like-abrasive-stone-dressed cast iron bond diamond wheel. A comparative study of surface characteristics of ground CVD-SiC has been carried out. The following conclusions have been drawn below. (1) The surface characteristics of wheels dressed by these two methods are different. (2) The surface roughness ground by ELID grinding was only slightly better than the one produced by the ordinary grinding method. (3) The microscopic characteristics of CVD-SiC ground by these two methods differed largely. (4) ELID grinding is greatly recommendable in precision grinding of hard-brittle materials on ordinary machines of low rigidity.