DEVELOPMENT OF A MICRO-DISPLACEMENT TABLE FOR ULTRA-PRECISION MACHINING AND GRINDING FOR CURVED SURFACES BY THE USE OF IT

This paper describes a positioning system and reports experimental results of the grinding for curved surfaces by using the system. In order to control the shape accuracy of ultra-precision grinding surfaces, a micro-displacement table and its control system have been developed. The table has three non-contact capacitive displacement transducers as sensors and three stacked piezoelectric ceramic actuators. In the grinding process, a microcomputer dynamically and precisely controls the positioning micro-displacement table so that it changes the relative position of the ground surface and grinding wheel. It is confirmed that three-dimensional curved surfaces with large curvature radii can be precisely obtained by means of automatic grinding operations with the table and its control system. Thus, it is expected that mirror surfaces having high shape precision can be ground on conventional grinding or cutting machines such as machining centers or surface grinders by attaching the system to them.