Edge Fracture Characteristics of Diamond Grains under Different Crystallographic Orientations in Stone Grinding Processes.

Abstract

In stone grinding processes, the variation of edge shape distribution of a diamond grain due to edge fracture was examined under different crystallographic orientations of the grain facet. Edge shape transition probabilities and fracture onset probabilities were obtained by a single-grain grinding test. From these values, the variation of existence probability of edge shape distribution was calculated, applying the theory of Markov process. As a result, edge fracture characteristics were found to vary both with the crystallographic orientation and with the cutting direction. Namely, when the {111} face of diamond grain was directed toward the grain tip and cut in the <100>direction, fracture onset probabilities exhibited the smallest value and large transition probability to sharp edges. Hence, the grain edges directed its direction, which maintain sharpness during grinding and long life time, have an advantage in grinding hard stones.