Heat Partition in Wet Grinding of Fine Ceramics: Studies on Grinding of Hard-brittle Materials (2nd Report)

摘要

This report deals with the grinding heat partition into workpiece for two kinds of fine ceramics-normally sintered silicon carbide (SSC) and normally sintered silicon nitride (SSN)-in wet grinding. Based on a simple model of heat transfer in wet grinding in such that some portions of the total grinding energy (=q) is conducted into workpiece as heat (=qw) and part of qw flows into grinding fluid by convection (=qf) through the ground surface in the wheel-work interference zone, the heat partition into workpiece Rw is calculated. The heat partition of SSC is not affected so much by both table speed and wheel depth of cut with water-based grinding fluid. In the case of SSN, on the other hand, Rw increases from approximately 5% to 35% as table speed increases from 0.2 to 15 m/min. At lower table speed below approximately 1 m/min, however, the heat partitions are little influenced by table speed, in which the fragmented finished surface like SSC is dominant. The abrasive-workpiece interaction of SSN is affected by the grinding zone temperature, so that the surface morphology varies with grinding conditions as well as grinding heat partitions under the conventional grinding conditions.