Crystal Plane Selection of Single Crystal Diamond Cutter

Diamond crystal belongs to the cubic crystal system. Different arrangement form of atoms on the crystal plane, the density of atoms and different distance between crystal planes, cause the anisotropy of natural diamond crystal, so the crystal planes of diamond cutter have not only different physical and mechanical properties but also different manufacturing difficulties and service life. The microscopic crippling strength of all crystal planes are also obviously different.

The microscopic strength of diamond crystal can be tested by Hertz. Because diamond is a kind of typical brittle material, the average deviation of intensity values is larger, which mainly relies on the morphology and distribution of the stress distribution. Thus, it is suitable for analysis with probability theory.

When the applied stress is same, the damage probability of (110) crystal plane is the largest, and the (111) crystal plane is the second, and the damage probability of (100) crystal face is minimal. Namely, under the action of external force, (110) crystal plane is easiest to be damaged, and (111) crystal plane is the second, and (100) crystal face is not easy to be damaged. Although the grinding rate of (110) crystal plane is higher than that of (100) crystal plane, the experimental results show that the (100) crystal plane has higher ability of stress, corrosion resistance and thermal degradation than other crystal planes.

To sum up, if the (100) crystal plane is used for the tool faces, it is easy to grind out high quality cutting tool edge, and not easy to cause the micro crack. Usually, we should select the crystal plane of single crystal diamond cutter according to the requirements of the cutting tools. In general, if you want diamond tools with  the highest strength, you should choose (100) crystal plane as the tool surfaces; If you want diamond tools with abrasion resistance, you should choose (110) crystal plane as the tool surfaces; If you want diamond tools with wear resistance to chemical, you should use (110) crystal plane as the rake face of cutting tools, and (100) crystal plane as the other side. These requirements all need the help of crystal orientation technology.