Design criterion for crystal orientation of diamond cutting tool

The crystal orientation on rake and flank faces of diamond cutting tool is a crucial factor affecting the finished edge quality so as to the surface integrity achieved in SPDT operation. In present work, therefore, a novel design criterion, i.e. the dynamic micro tensile strength of diamond crystal, is proposed to optimize the orientation on rake and flank faces of diamond cutting tool. For tool making by means of mechanical lapping, the factual polishing direction must be parallel to the ‘soft’ orientation of lapped tool facet. So that while the cutting edge is desired to be finished sharply as possible, the largest dynamic micro tensile strength being oriented paralleling to the polishing direction, i.e. the ‘soft’ direction of lapped tool face, is best favorable. For tool utilization, the visible wear generally takes place on flank face. If tool durability is expected to be as long as possible, the flank face should be oriented having great enough dynamic micro tensile strength along the cutting direction. Finally, a large number of tool polishing and wear experiments are carried out, and the collected results accord with the design intention well, which validates the proposed criterion is suited for directing the design of diamond cutting tool.