How to Reasonably Use Diamond PDC and PCBN Cutter?

With the development of large diameter polycrystalline diamond compacts (PDC), the application of diamond tools has also been extended to the industrialized mass production, especially in automotive and carpentry industry. Diamond is replacing the traditional cutting tool material because of its excellent properties. The diameter of the PDC is up to 74mm. Because PDC has consistent and stable performance and cost-effective advantage, the development of material is also very quickly in other areas.

PDC (polycrystalline diamond) has high wear resistance, thus it is the ideal material for making wear-resisting devices (suitable for use in the contact surface of ferrous and non-ferrous metals). We find that the cutter welding Syndite in production compared with wear-resisting components and traditional products, such as cemented carbide, has higher performance that is up to thirty times and even hundreds times, which is also related to specific applications.

Cubic boron nitride is high performance cutting tool materials that process quenching iron group metals and alloys, but the synthesis of CBN is implemented under the condition of high temperature, subject to the conditions of high pressure chamber and the difficulties brought about by the synthetic technology, it is difficult to get high quality large particles CBN monocrystal. The size of CBN monocrystal is usually under 0.5mm, the largest about 3mm. Thus, the size is too small if it is used as a tool. 

Second, although cubic boron nitride single crystal is very hard, the application performance is not ideal in the part of the processing because of the influence of crystal cleavage mechanism. In this case, the CBN polycrystalline, especially polycrystalline composite with the substrate, arises at the historic moment. Its emergence not only can solve the problem of the size of the CBN, but also make the CBN toughness has been greatly increased because these materials are polycrystalline organization and there is no cleavage problem. CBN polycrystalline gets rapid development because of this point. 

CBN polycrystalline with the binder: the materials used for CBN polycrystalline binder are very extensive, and are roughly divided into the following three categories: A. The metal or alloy binder, such as nickel, cobalt, titanium, aluminum, copper and their alloy; B. The metal ceramic bond made of metal, alloy and ceramic, including carbide, nitride, boride, silicide series ceramic metal, such as titanium carbide, zirconium carbide, boron carbide, titanium nitride, boride titanium, silicide aluminum, etc.; C. The nonmetal and boron compounds, such as silicon, Me 3 B 2 N 4 (Me for alkaline earth metal), etc.

CBN composite film: Cubic boron nitride polycrystalline without substrate overcome the anisotropy of single-crystal cubic boron nitride and the characteristic of the small crystal size, but there is the problem about connection and welding when doing the cutting tools. It is actually quite difficult by using the hard and brittle and difficult to be generally solder by infiltrating and caking of cubic boron nitride polycrystalline sintered body to directly weld. The solder with low melting point and easy to welding is often a lack of adequate mechanical strength, while the solder of high melting point may make the polycrystalline performance deteriorated even burned in danger in welding (cubic boron nitride often in the metastable state, unstable in the case of high temperature and pressure). And making cubic boron nitride particles and additives and cemented carbide substrate under the condition of high temperature and high pressure sintering into cubic boron nitride composite film will solve this problem successfully, and the application of PCBN composite film will also be more convenient.