Contour Grinding of Ceramics with Diamond Microquill

This paper introduces contour grinding of ceramics with an electroplated diamond microquill (wheel) of which the diameter is less than 1 mm. A contour grinding machine was developed for this experiment. The machine has an ultra-precision air spindle with a maximum revolution speed of 120 000 rpm, an XY slide table with AC servo motors for positioning of the workpiece, and a dynamometer unit for force-controlled machining. This machine, therefore, can be used for simultaneous two-axis linear or circular path contouring. In this paper, basic grinding characteristics were investigated in linear cutoff grinding of an aluminum nitride board. The main results obtained are as follows ; (1) The grinding force becomes smaller and the quill life becomes longer as the grit size of the diamond grain increases. (2) With increasing work speed, the total cutting length increases. (3) At a low work speed, the adoption of the workpiece oscillation which is perpendicular to the cutting direction has an effect on quill life.