Diamond anisotropy, so not only the crystal surface hardness, wear resistance is different, that is, the same crystal surface in different directions wear resistance is also different. If the crystal orientation is improperly selected, the sharpening efficiency will be greatly reduced even if the crystal face is properly selected. At the same time as the diamond crystal compressive strength than the tensile strength of 5 to 7 times, so in the sharpening process to choose the easy-to-wear direction of the crystal surface, while the edge to meet the blade grinding wheel linear speed in the positive direction (that is taken Inverse grinding) to ensure sharpening efficiency and reduce the micro-level edge cleavage.