Metal cutting machine tools provide a great platform and guarantee for mechanical manufacturing. Good cutting tools should have high hardness and flexibility, especially with the application of high-speed machining technology, dry cutting, and other technologies, the requirements for cutting tools are becoming higher and higher. In fact, there are five kinds of commonly used materials for cutting tools on CNC machine tools. These five materials basically have the characteristics of high hardness, high wear resistance, and high heat resistance.
What are the most common materials used to make CNC cutting tools, and what are the advantages and disadvantages of different materials?
1. High-speed steel
It is a tool steel with high hardness, high wear resistance, and high heat resistance, also known as high-speed tool steel or front steel, commonly known as white steel. Therefore, it is mainly used to manufacture complex thin edge and impact-resistant metal cutting tools. The manufacturing process of high-speed steel tools is simple and easy to grind into sharp cutting tools. Therefore, despite the continuous emergence of various new tool materials, high-speed steel tools still account for a large proportion of metal machining.
2. Cemented carbide
Cemented carbide is an alloy material made of a hard compound of refractory metal and bonding metal by powder metallurgy process. Because it has a series of excellent properties such as high hardness, wear resistance, good strength and toughness, heat resistance, and corrosion resistance, especially its high hardness and wear resistance, it remains basically unchanged even at 500 ℃ and still has high hardness at 1000 ℃. Therefore. The cutting performance of cemented carbide is much higher than that of high-speed steel, and the tool durability can be increased by several times to dozens of times. At the same time, the cutting speed can be increased by 4-10 times. Cemented carbide is widely used as tool material, and can also be used to cut difficult machining materials such as heat-resistant steel, stainless steel, high manganese steel, and tool steel.
Diamond is the material with the highest hardness and the best thermal conductivity among the known mineral materials. The wear amount of diamond paired with various metal and non-metallic materials is only 1/50-1/800 of that of cemented carbide. It is the most ideal material for making cutting tools. However, artificial single crystal diamond is often used as cutting tools. The cutting edge of the diamond tool is very sharp (which is very important for cutting chips with very small cross-sections), the roughness of the edge is very small, the friction coefficient is low, it is not easy to produce chip nodules during cutting, and the machining surface quality is high. There are three kinds of diamond cutters: natural single crystal diamond cutter, integral artificial single-crystal diamond cutter, and diamond composite cutter. Natural diamond cutting tools are rarely used in practical production because of their high cost.
4. Cubic boron nitride
It is a new synthetic material developed in the 1950s, which is sintered by CBN dice powder and a small amount of bonding phase (Co.Ni or tic, tin, A1203) added with catalyst under high temperature and high pressure. It has high hardness, good wear resistance, excellent chemical stability, much higher thermal stability than diamond tools, and has no chemical reaction with iron group metals at 1200-1300 ℃. It can be used to process steel. Therefore, PCBW tools are mainly used for the efficient processing of black difficult-to-process materials and are widely used in the machining industry.
The main advantages of ceramic tool materials are: high hardness and wear resistance and little reduction in bending strength and wear resistance at high temperatures. It has high chemical stability, a low affinity between ceramic and metal, and good oxidation resistance at high temperatures. It does not interact with steel even at melting temperature. Therefore, the bonding, diffusion, and oxidation wear of cutting tools are less. With a low friction coefficient, chips are not easy to stick to the knife, and chip accumulation tumor is not easy to occur. The disadvantages of the ceramic cutter are: high brittleness, low strength and toughness, and the bending strength is also weaker than that of cemented carbide.