Cubic boron nitride polycrystalline (PCBN) cutters are a class of superhard materials made from many fine grain (0.1~100) CBN Poly-CBN Aggregates. In addition to its high hardness, high abrasion resistance, but also has a high toughness, chemical inertia, red hardness and other characteristics, and can be used to open the diamond grinding wheel. In all aspects of the cutting process has shown excellent cutting performance, to achieve stable cutting at high temperatures, especially suitable for processing a variety of hardened steel, tool steel, chilled cast iron and other difficult materials. Tool cutting sharpness, good conformal, high wear resistance, unit wear, small number of corrections, for automatic processing, suitable for all machining from roughing to finishing. Precision car quenching workpiece is a new process, the implementation of the process to be done before the test, can be used with the workpiece material, hardness and size of the same bar material, in the same machine on the finishing or roughing test, the key is to test the choice of tool and cutting parameters and the process system is sufficient rigidity.
The process is currently used in the domestic, such as FAW Group with PCBN cutting tool carburizing quenching (58~63HRC) 20CrMnTi gearbox Gear fork groove, the use of the process parameters for the υc=150m/min, f=0.1mm/r,αp=0.2~0.3mm, to achieve a car-based grinding. When turning hardened steel with PCBN tool for machining hard cast iron, it is required that the workpiece quenching hardness is higher than 45~55HRC, and when the hard cast iron is processed, the hardness reaches the medium hardness level (45HRC), it will get good processing effect. such as the exhaust valve seat on the cylinder head of the automobile engine, the valve seat is a high chromium alloy iron material containing copper, molybdenum, its hardness is generally about 44HRC, the valve seat on the hole using a countersink (hinge), the car two processes, mostly in a dedicated automatic line processing, with the gun hinge conduit hole. The cutting dosage used is: υc=71.6m/min,υf=26.5mm/min,αp=1.0mm, the use of BC Broaching oil, since the use of PCBN tool processing, with the previous use of a variety of carbide blade processing compared to the average tool durability of 1200 pieces, The machining surface roughness is ra0.4μm, the valve seat face swings ≤0.05mm. Dongfeng Motor Company engine plant since 1988 using PCBN tool, its effect has remained stable, better to solve the imported equipment localization of the tool.