Simulation of cBN Grain Wear During Single Grain Engagement Considering Cleavage Planes

Abstract

A large part of the energy introduced during grinding is converted into heat. As not all the heat can be dissipated by the cooling lubricant, thermally induced displacements in machine components occur. These displacements have a negative influence on the component quality. Since the grinding wheel topography changes during the grinding process due to wear, the wear mechanisms of grain splintering, grain breakage as well as abrasion were identified and quantified. In addition, their effect on heat generation was investigated. To predict the wear mechanisms, a Finite Element (FE) simulation model was developed that determines the grain shape change considering the cleavage planes in the grain. Three-dimensional real cBN grain geometries were used for the simulation of a single grain engagement in the workpiece of the 100Cr6 steel. In the presented model, the orientation of the cleavage planes is varied and their influence on the wear mechanisms as well as the resulting forces is investigated. In addition, empirical tests were conducted in order to adjust the model. The simulation showed that a cleavage plane variation resulted in stronger crack propagation when the cleavage plane was oriented away from the workpiece and when the distance of the cleavage plane from the point of application of the load was smaller.