Polycrystalline diamond, (PCD) is currently used in the industry for cutting tools of difficult-to-machine materials because of its superior characteristics such as hardness, toughness and wear resistance. But the PCD material is difficult to machine due to its above properties. Before making the PCD blank in varies tools, the lapping process is essential and necessary. The lapping quality depends heavily on the parameters. Therefore it is of great significance to study the path and velocity of lapping process for ensuring the lapping quality and uniform wear of abrasive disk. In this paper, on the basis of kinematics and geometry principle, the path equation was established. The complicated lapping process can be converted into two rotation movements, i.e. the movement of part against the center of lapping disk and rotation of fixture around its center. The relative path and relative velocity of random point of the part against abrasive disk were also analyzed and calculated. The computer simulation software was developed for figuring the path curves and instantaneous velocity of the lapping process. The results show that the abrasive disk can wear uniformly and the lapping quality can be raised. The application of computer simulation software provides the possibility to analyze the lapping principles, which is a simple, convenient and effective method.

Arcjet plasma enhanced CVD was used to grow diamond. Nucleation of diamond was studied at the early stage of growth cause. The micro-structural probes (transmission electron microscope (TEM), high resolution electronic microscope (HREM), selected area diffraction (SAD) and electron energy loss spectra (EELS) were used to characterize the nuclei. It was found that nuclei formed following the amorphous carbon formation. The critical nucleus size was deduced to be less than 20 nm. The growth of nucleus would form the network-like structure. The incubation period of nucleation was deduced as 6–8min under the condition of high concentration of CH4 in H2.

Ar\H2\CH4 gas mixture was utilized to grow nanocrystal diamond films in a RF plasma enhanced CVD system. CH4\ H2 ratios were changed to study the effect of plasma radicals on the deposit, in which optical emission spectroscopy (OES) was applied to analyze the plasma radicals. It was found that Hα, Hβ, Hγ, CH, C2 were the main radicals in the plasma. Among them, the CH intensity of OES was usually quite strong and increased sharply when the ratio of CH4/H2 was greater than 3%. The intensity of C2 was weak and basically unchanged with the addition of methane. This study can provide a new possible technical application for depositing NCD films.