Abstract

Glass, an ancient yet innovative material, has always held a particular fascination. We are surrounded by glass in almost all areas of life, in the home by window glass, television and computer screens, by wine glasses etc., and by high-tech products such as glass fibres, micro-optics, aspherical precision lenses etc. The problems involved in machining all types of glass are summed up by the expression: "Glass retains its shape until it reaches breaking point" which, at the same time defines the dominant characteristic of float and optical glass. The brittle nature of glass is the major influencing factor on the material removal mechanism when glass parts are machined using diamond wheels with metallic bonds. Glass chips are removed by inducing fractures. Under certain boundary machining conditions, however, it is possible to achieve a viscous flow of the glass material. This principle is known as ductile material removal. By producing a very finely-structured surface, the ductile grinding process reduces or eliminates the need for a polish-finishing operation. This paper describes the dominating parameters on ductile chip formation and illustrates some special applications.

© 1998 Optical Society of America