Introduction to diamond tool materials
Wooden Flooring,Engineered Wood Flooring,Wood Floor Laminate flooring Co., Ltd. , http://www.nslaminate.com
1. Natural single crystal diamond
Natural single crystal diamond is an anisotropic single crystal. Hardness up to HV9000-10000, the hardest substance in nature. This material has excellent wear resistance, and the cutting of the tool can maintain dimensional stability for a long time, so it has a long tool life.
The natural diamond tool cutting edge can be machined to extremely sharp. It can be used to make ophthalmic neurosurgical scalpels; it can be used to process contact lens surfaces; it can be used to cut optical glass fibers; it can be used to process gold and white gold jewelry patterns; the most important use is for high-speed super-finishing non-ferrous metals and their alloys. Such as aluminum, gold, babbitt, beryllium copper, copper and so on. The super-finishing tool made of natural diamond has a circular arc portion of 400 times under the microscope and is free from defects. It is used for processing aluminum alloy polyhedral mirrors, oxygen-free copper laser mirrors, gyroscopes, video recorder drums, and the like. The roughness of the expression can reach Ra (0.01-0.025) μm.
Natural diamond materials have poor toughness and low flexural strength, which is only (0.2-0.5) Gpa. Poor thermal stability, loss of hardness when the temperature reaches 700 ° C -800 ° C. When the temperature is higher, it will carbonize. In addition, it is very strong with iron and is generally not suitable for processing steel.
2, artificial single crystal diamond
Artificial single crystal diamond is used as a tool material, and industrial grade single crystal diamond material produced by DE-BEERS is currently available on the market. This material is slightly less rigid than natural diamond. Other properties are comparable to natural diamonds. Due to the manual manufacture, the size of the cleavage direction becomes controllable and uniform. With the development of high temperature and high pressure technology, the maximum size of artificial single crystal diamond can be achieved 8mm. Because of the relatively good consistency and low price of this material, it has received widespread attention. As an alternative to natural diamond new materials, the application of artificial single crystal diamond will be greatly developed.
3, artificial polycrystalline diamond
Synthetic polycrystalline diamond (PCD) is a polycrystalline material obtained by solvent-polymerizing diamond micropowder under high temperature and high pressure. In general, a solid circular piece of cemented carbide is used as a matrix, which is called a polycrystalline diamond composite sheet. According to the thickness of the diamond matrix, the composite sheets have different specifications such as 1.6mm, 3.2mm, and 4.8mm. The thickness of polycrystalline diamond is generally about 0.5 mm. At present, the domestic production of PCD diameter has reached 19mm, while foreign countries such as GE's largest composite sheet diameter has achieved 58mm, De Beers company has reached 74mm.
According to the tool making, it is necessary to cut the cutter heads of different sizes with laser or wire cutting to make turning tools, boring tools and milling cutters.
PCD hardness is lower than natural diamond (about HV6000), but the flexural strength is much higher than natural diamond. In addition, by adjusting the particle size concentration of diamond micropowder, the mechanical and physical properties of PCD products are changed to meet the needs of different materials and different processing environments, providing a variety of options for tool users.
PCD tools have much higher impact and shock resistance than natural diamonds. Compared with cemented carbide, the hardness is 3-4 times higher; the wear resistance life is 50-100 times higher; the cutting speed can be increased by 5-20 times; the roughness can reach Ra0.05μm. High cutting efficiency and stable machining accuracy.
Like natural diamond, PCD is not suitable for processing steel cast iron. This tool is mainly used for processing non-ferrous metals and non-metallic materials, such as: aluminum, copper, zinc, gold, silver, platinum and their alloys, as well as ceramics, carbon fiber, rubber, plastics and so on. Another major feature of PCD is the processing of wood stone.
PCD tools are particularly suitable for processing high-silicon aluminum alloys, so they are widely used in the automotive, aerospace, electronics, and marine industries.
4, CVD diamond film
CVD Diamond Thick Film A chemical vapor deposition method for forming diamond materials. As a tool material, its hardness is higher than PCD. Due to the absence of metal binders, it has high thermal conductivity and high temperature oxidation resistance. However, the current production of CVD materials is relatively tough, and it cannot be cut by wire cutting, and the use is limited. Since there is no directionality, the grinding process is poor, and it is extremely difficult to sharpen the sharp edge like natural diamond artificial single crystal diamond. As a cutting tool, it is still in the experimental stage and needs further research and development.