Microfracture of Diamond as Fine Tool Material

This paper deals with the principle for the design of an anti-chipping diamond cutting tool for fine machining. Eased on both the statistical analysis of brittle fracture and the microstrength measurement by specially designed procedures, the fracture criterion is proposed for diamond as a cutting tool material. The criterion describes well the statistical nature and the anisotropy in the fracture strength of diamond. The stress distribution in a cutting edge, as a basic parameter for fracture analysis, is computed for a typical cutting condition. By comparing the stress level in a cutting edge with the statistical microstrength properties of diamond, probabilistic prediction of the cutting edge chipping can be successfully made. Analysis by the method proposed shows numerically the remarkable effect of the crystal orientation on the cutting edge chipping or fracture in diamond tool.