The Comparison Study On Cutting Performance With PCBN Compact Tools

The PCBN cutting tool has excellent superiority in machining accuracy, efficiency and tool life because of its great hardness, high wear resistance and super chemical stability. However, the cutting performance of PCBN cutting tool is directly influenced by the sintering technology and match parameter of PCBN compact. It is generally agreed that the hardness of PCBN cutting tool can be higher with a higher CBN content, and better surface quality of workpiece can be obtained with smaller CBN grains. But the binder's variety and content have a complicated impact on the performance of PCBN compact as well as the CBN grains quality, sintering technology, etc. Therefore, it is significant to compare the quality of PCBN compact made by different manufacturers, analyze the tool's cutting property and the difference of thefinished surface quality, and research the wear mechanism of various cutting tools for selecting suitable tool material to enhance tool life and improve the cutting economy and manufacture level of PCBN compact.The comparison experiments of the tool wear, cutting force and surface roughness have been done to study the two kinds of PCBN compact, which are produced by several companies, and respectively designed to machine hardened steel and austempered ductile iron. The results indicated that, in the cutting experiment of hardened steel, DBC50 and BN500 compact tools which adopted Ti base binders have a better performance compared with SB80 and homemade compacts, which used Al, Co as the main binders separately. The DBC50 compact tool, which contains more C in the binders, has the best abrasion resistance, the lowest cutting force and friction coefficient, but worse shock resistance. The abrasion resistance of BN250 compact tool, which contains more N in the binders, takes the second place while it has the best thermal stability and chemical wear resistance. On the other hand, the wear resistance of SB80 and homemade compact tools is the worse, while the cutting force and friction coefficient of the later are larger due to its large size and high content of CBN grains. The PCBN compact tools, which were employed to machine ADI, worn quite fast because of oxidation, diffusion, adhesion and chip. The tool lives of DBA80, SB95 and homemade compacts which contain more Al, W, Co in the binders are much shorter than that of BN500 which contains Hf and a lower content of CBN. Furthermore, the smaller cutting force and friction coefficient of BN500 compact tool made it fit for ADI machining greatly. All the chose tools maintained the machining surface quality well during the machining process. The surface roughness of hardened steel machined by BN250 and SB80 compact tools is lower than Ra0.80, which is much better than machined by the DBC50 and homemade compact tools. At the same time, the surface roughness of machined ADI is all below Ra0.80.