Research on predicting model of surface roughness in small-scale grinding of brittle materials considering grinding tool topography

摘要

In this paper, grinding tool surface topography was measured by a laser displacement sensor system, a series of data of grain protrusion height and grain vertex angle then were obtained. Based on the obtained grain protrusion height and grain vertex angle, a surface roughness model considering material ductile and brittle removal mechanism, grain protrusion condition, material property and machining parameters was built. In order to validate the surface roughness model proposed, experiments have been conducted on aluminum oxide ceramics and single crystal silicon by using a multi-hump grinding tool. It is found that brittle fracture has an important effect on surface roughness, the variation trends of surface roughness and brittle percentage are rising quickly first and then rising steadily with increased feeding velocity. For aluminum oxide ceramics and single crystal silicon, surface roughness of big diameter tool is averagely 2% and 6% lower than small diameter tool, respectively. The average surface roughness of single crystal silicon is about 34% smaller than aluminum oxide ceramics, the corresponding values are 0.498 mu m and 0.760 mu m respectively. In respect of the model accuracy, the average error of the 32 sets of data for aluminum oxide ceramics is about 15%, for single crystal silicon is about 11%. The surface roughness model proposed in this paper will help a lot to further improve the prediction of surface roughness.