Abstract

Fine grinding or ductile grinding is a way of putting a shiny surface on certain types of glass. As such, it is an alternative to conventional polishing, and offers the possibility of mass production of aspheric or other hard-to-produce shapes on lenses and mirrors. However, the parameters of ductile grinding are only imperfectly understood. A key factor is the stability of the machine used for the ductile grinding. Recently an ultra-precision surface grinder has been built¹ that contains a low expansion Zerodur glass ceramic spindle to eliminate the changes in length (and hence depth of cut) that result from temperature changes during machining. Studies have been made with this machine to determine the optimum conditions for operating the diamond-impregnated grinding wheels to obtain the smoothest surface finish.² These conditions are: a surface rotation speed of the wheel ~1200 meter/min, rotation speed of the workpiece ~0.01 meter/min, and depth of cut ~0.2 μm, making a repeating groove pattern of 3.6 μm, much like a diamond-turned surface.

© 1990 Optical Society of America