In the past 30 years, tool coating technology has developed rapidly and coated tools have been widely used. In 1969, Germany's Krupp and Sandvik developed a chemical vapor deposition (CVD) coating technology and introduced CVDTiC coated carbide inserts to the market. In the early 1970s, R. Runshan and A. Raghuran developed the physical vapor deposition (PVD) process and in 1981 introduced PVDTiN high speed steel tool products to the market. At that time, the CVD coating process temperature was about 1000 ° C, mainly used for the surface coating of cemented carbide tools (blades); PVD coating process temperature is 500 ° C and below 500 ° C, mainly used for surface coating of high speed steel tools.
Later, CVD and PVD coating technologies continued to develop rapidly, and great progress was made in coating materials, coating equipment and processes, and the coating technology of multilayer materials was developed to enable coated tools (blades). The performance has been greatly improved. PVD coating technology used to be mainly used for high speed steel tools. In recent years, with the rapid development of PVD coating technology, it has also been successfully used in cemented carbide tools (blades), occupying half of the positions of carbide coated tools (blades). . Nowadays, coated high speed steel tools and coated carbide tools (blades) are widely used, accounting for more than 50% of the total tool use.
Advantages of coated tools
Surface coating on a tough tool (blade) substrate, coating a thin layer (such as TiN, TiC, etc.) with high hardness, high wear resistance and high temperature resistance, so that the tool (blade) is comprehensive and good. Comprehensive performance. The hardness of uncoated high-speed steel is only 62~68HRC (760~960HV), the hardness of cemented carbide is only 89~93.5HRA (1300~1850HV); and the surface hardness after coating can reach 2000~3000HV.
1 Due to the high hardness and wear resistance of the surface coating material, and high temperature resistance. Therefore, compared to uncoated tools (blades), coated tools allow for higher cutting speeds, which improves machining efficiency; or increases tool life at the same cutting speed.
2 Since the coefficient of friction between the coating material and the material to be processed is small, the cutting force of the coating tool (blade) is smaller than that of the uncoated tool (blade).
3 It is processed with coated tools (blades), and the processed surface quality of the parts is good.
4 Due to the comprehensive performance of the coated tool (blade), the coated cemented carbide insert has better versatility, and a coated carbide grade insert has a wider range of use.
Development and advancement of tool coating technology
The author visited the International Machine Tool Exhibition for many times, collected a lot of materials, and listened to the technical reports of major tool companies to understand the development and progress of the surface coating technology of tool products.
Progress in CVD coating technology
In the past, the surface coating of cemented carbide tools was a high temperature chemical vapor deposition (HTCVD) process. In a normal or negative pressure deposition system, pure H2, CH4, N2, TiCl4, AlCl3, CO2 and other gases are uniformly mixed according to the composition of the deposit according to a certain ratio, and sequentially applied to a certain temperature (generally 1000) ~1050 ° C) cemented carbide blade surface, that is, deposited on the surface of the blade TiC, TiN, TiCN, Al2O3 or their composite coating. Until now, HTCVD is still the most used process. In addition to HTCVD, there is also a plasma chemical vapor deposition (PCVD) process, which is another method of coating the surface of cemented carbide tools (blades). The coating process temperature is low (700~800 °C), so the bending strength of the blade is reduced. Because TiC is the closest to the linear expansion coefficient of the matrix material, it is usually coated on the surface of the substrate with a thin layer of TiC, and then coated with TiN, Al2O3, such as TiC/TiN, TiC/Al2O3, TiC/TiCN/TiN, and the like.
Later, multilayer coatings of various combinations were developed. The author has investigated and counted CVD coated cemented carbide inserts from various companies in Sweden, Germany, the United States, Japan, Korea, Israel and China at various exhibitions. The coating materials have the following combinations: TiCN/Al2O3, TiCN/TiC /TiN, TiCN/TiC/Al2O3, TiCN/Al2O3/TiN, TiCN/TiC/Al2O3/TiN, TiCN/Al2O3/TiCN, TiN, TiC/TiCN/TiN, TiN/TiCN/TiN, and the like. It can be seen that in recent years, TiCN or TiN has been used as the bottom layer. This is because the base cemented carbide has been improved. For example, a gradient structure is used to make it possible to use TiCN or TiN. In addition, the TiN coating should not be used alone because the hardness of TiN is not much improved compared with cemented carbide, and TiN must be used in combination with TiC, TiCN, Al2O3, and the like.
Progress in PVD coating technology
In the early days, the PVD coatings were all vacuum-evaporated. The layers were often uneven, and the bond with the substrate was not strong enough. After the development of the "vacuum magnetron sputtering method" and the "vacuum plasma plating process", the effect was very good. The latter two methods are mainly used for tool surface coating.
In the early years, PVD coatings were only used for high speed steel tools, and the coating material used almost exclusively TiN. Later, the coating process was improved, a variety of coating materials and multilayer coatings were developed, and a large number of applications were also applied to cemented carbide tools. The coating effect is much better than before. TiN coating materials are still in use, and the emerging coating materials are TiAlN and AlTiN, which are superior to TiN.
Europe has the highest level of PVD coating technology and is ahead of other countries and regions. Well-known manufacturers include Oerlkon Balzers, PVT Plasma Vacuum Technologies of Germany and Unimerco of Denmark. Their PVD coating equipment and process are advanced, with a wide range of coating materials, coating tools and other products with good performance.
Some well-known high-speed steel and carbide tool factories in foreign countries have coated tool (blade) products, but the coating equipment and processes are mostly purchased from or specialized in coating technology companies, rather than self-developed. It is reported that the PVD coating equipment of Sweden Sandvik and Israel Isca is purchased from Oerlikon Balzers. China should do the same, which is a good and fast road. For example, China Harbin No. 1 Tool Factory and German PVT Company established a Harbin Yipu Puwei Coating Cooperative Joint Stock Company. Oerlikon Balzers has 77 coating centers around the world, and a center in Suzhou, Tianjin and Hanjiang, China. Tool manufacturers in neighboring cities and regions in China, coating products are mostly coated at the above centers. The coating equipment of Hunan Zhuzhou Cemented Carbide Plant and Sichuan Zigong Great Wall Cemented Carbide Plant were imported from abroad.
Next page
TUV approved Bulb Fixture series include the Track Light fixture, Ceiling Light fixture, Pendant Light fixture, downlight fixture, grill light fixture. It's used to match the GU10, MR16, E27, E26 bulbs.
This kinds of fixture is very easy to replace the bulb if it's faulty, It's can help customer saves a lot of after-sale cost. And the appearance of our bulb fixtures are as fashion as the normal led luminaire.
Various color Bulb fixture avaliable: White, black, silver, gold, cooper, chrome, wood and customized color with RAL no. are acceptable as well.
Fast delivery time for Bulb fixture: 5-7days of samples, 15days of bulk orders
Bulb Fixture,Light Bulbs For Outside Fixtures,Porch Light Bulb,Light Bulbs For Chandeliers
Jiangmen Dilin Lighting High-Tech Co., Ltd. , https://www.jmdilinlighting.com