1. Preface:
The cemented carbide tool, which was first developed by the germans in 1926, has become one of the most important cutting tools in more than 80 years. PCD and PCBN are also important tools. The superhard materials are discussed in this paper three kinds of new technology, a new type of PCBN used in high speed machining cast iron grade, drilling CFRP with diamond plating of cemented carbide and tungsten carbide milling directly with BL - PCD face milling.
2. Cast iron high-speed milling with CBN.
Cubic boron nitride (CBN) has high hardness, good thermal conductivity, and is not easy to react with iron material, second only to diamond. Polycrystalline cubic boron nitride (PCBN) is made by sintering CBN particles with ceramic binding agent. PCBN promotes the hardening steel processing technology from grinding to cutting. The PCBN cutting tools produced by Sumitomo Electric Hardmetal can significantly improve the production efficiency and reduce the cost in the precision and semi-finishing processes of iron materials such as cast iron. On the other hand, due to the high strength of PCBN and good thermal conductivity, it is applied to high precision machining of cast iron. For example, the surface processing of the engine unit and oil pump is usually done with the PCBN cutting tool. This paper mainly discusses the milling of cast iron by new PCBN tools.
There are two types of PCBN sinter: one is to bond CBN particles to the binding agent; The other is to use a small amount of binder material to bond the CBN particles together. The former has good wear resistance and is cut with hardened steel. Otherwise, the CBN content is high and the thermal conductivity is good. It is used in cast iron processing, heat resistant alloy and PM parts. BN7000 is the latter.
BN7000 has higher CBN content than other traditional PCBN grades, with high strength, good toughness, high hardness and good thermal conductivity. The CBN content increased from 90 vol% to 93vol% by using the sintering pressure above the usual 5GPa. In order to reduce the abrasive wear of binder, the binding dose of BN7000 sintered was reduced by 30%. In the sintering process, the CBN particle reaction is accelerated to improve the composition of the binder, so that the binding strength of the binder is much larger than that of the traditional binder.
3. CFRP processing with diamond plating tools.
It is a characteristic of composite materials to combine the matrix and reinforced materials to form a controllable mechanical characteristic. Carbon fiber reinforced plastic (CFRP) is widely used in industrial machinery such as automobiles, helicopters, medical equipment and railway vehicles due to its superior tensile strength, humidity and corrosion resistance. In addition, CFRP materials are a basic structural material in the aerospace field, which can reduce the weight of aircraft fuselage so as to improve fuel efficiency and save maintenance costs.
Direct milling of hard alloy.
In the process of mold preparation, to improve the precision of the mould, it is usually used to process direct milling with the carbide end milling. As the manufacturer to the improvement of die hard, appeared the polycrystalline diamond (PCD) cutting tools, diamond plating with carbide cutting tools and single crystal diamond cutter (SCD), direct milling can be used for hard material.
The hardness of the traditional PCD tool is not sufficient for the direct milling of hard alloy mold. SCD is not strong enough, and PCD and diamond plating tools are not very sharp. Therefore, no binder nano-polycrystalline diamond (bl-pcd) was born. The hardness of bl-pcd is higher than that of PCD and SCD, which is better than PCD and diamond plating. Suitable for the direct milling of hard alloy dies, especially finishing.
