PCD cutting tools have high hardness, high compressive strength, good thermal conductivity and wear resistance, and can obtain high machining accuracy and efficiency in high-speed machining.
The above characteristics are determined by the crystal state of diamond. In the diamond crystal, the four valence electrons of carbon atoms form bonds according to the tetrahedral structure, and each carbon atom forms covalent bonds with four adjacent atoms, thus forming a diamond structure. This structure has strong binding force and directionality, thus making the diamond extremely hard. Because the structure of polycrystalline diamond (PCD) is a sintered body of fine-grained diamond with different orientations, its hardness and wear resistance are still lower than that of single crystal diamond despite the addition of binder. However, PCD sintered body is isotropic, so it is not easy to crack along a single cleavage plane.
2. Differences in performance indicators
The hardness of PCD can reach 8000HV, 80~120 times of that of cemented carbide; In short, PCD has a long service life and improves production efficiency.
The thermal conductivity of PCD is 700W/mK, 1.5~9 times of that of cemented carbide, and even higher than that of PCBN and copper, so the heat transfer of PCD tools is fast;
The friction coefficient of PCD is generally only 0.1~0.3 (the friction coefficient of cemented carbide is 0.4~1), so PCD tools can significantly reduce the cutting force;
The coefficient of thermal expansion of PCD is only 0.9 × 10^-6～1.18 × 10 ^ – 6, which is only 1/5 of cemented carbide, so the thermal deformation of PCD tool is small and the machining accuracy is high;
The affinity between PCD tool and nonferrous metal and non-metallic materials is very small, and the chips are not easy to bond on the tool tip to form a chip deposit during processing
Post time: Feb-23-2023