Current situation and development trend of the mos

2022-07-26
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In recent years, with the promotion of high and new technologies such as microelectronics technology, computer technology, information engineering and material engineering, the traditional manufacturing technology has developed rapidly and has rapidly developed into a new manufacturing technology - digital manufacturing technology. Compared with traditional manufacturing technology, its important feature is that NC machining technology has been widely used. The driving force of this development comes from the strong pursuit of product manufacturing efficiency in the manufacturing industry. Under this background, the tool manufacturing and application technology, which mainly serves the manufacturing industry, has developed rapidly. A large number of high-speed, high-efficiency, flexible, compound and environmental protection NC machining tools and new application technologies are emerging, which has fundamentally changed the traditional cutting technology. Nowadays, hard cutting, dry cutting and high-speed and high-efficiency machining have become the important symbols of modern cutting technology, and drive the overall improvement of cutting technology, and have become the key technologies of NC machining. Cutting tool products have developed into products with high added value and high-tech content, including the latest achievements in the fields of contemporary materials, information science, computer and microelectronics application technology

1. At present, the main characteristics of the development of tool materials are: on the one hand, cemented carbide has replaced high-speed steel as the main tool material; On the other hand, the use proportion of superhard tool materials has increased significantly

1.1 in terms of cemented carbide matrix

(1) the development of new grades of cemented carbide is becoming more and more targeted

for example, Kennametal of the United States only has the following turning grades for different processed materials: kc9110 for processing steel, kc9225 for processing stainless steel, ky1310 for processing cast iron, kc5410 for processing heat resistant alloy, kc5510 for processing hardened materials, ky1615 for processing non-ferrous materials, Compared with the original brand, the cutting efficiency of the new brand can be increased by 15% ~ 20% on average. The new grades of TK1000 and tk2000 for processing cast iron introduced by the company can increase the cutting speed by 20% ~ 30%, while the tp3000 developed by the company for processing steel parts has good reliability in the application of heavy cutting, intermittent cutting and large feed

cast iron and stainless steel are two widely used workpiece materials at present, but their machinability is very different. Many companies have developed special brands for processing these two materials. For example, the black diamond blade series developed by Zhuzhou Diamond Cutting Tool Co., Ltd. is a cemented carbide blade specially used for processing cast iron, including ybd052 for dry high-speed processing of gray cast iron, ybd102 for high-speed processing of nodular cast iron, ybd152 for medium and high speed or milling, and ybd252 for medium and low speed wet milling or turning under intermittent conditions. Compared with the original brands, these new brands can increase the cutting speed by 30% ~ 40% and the service life by nearly 40% ~ 50%. In terms of processing stainless steel, the gc2015 turning austenitic stainless steel by Sandvik company of Sweden is a matrix with gradient zone resistant to plastic deformation and improved thermal hardness. In addition, the tin tin/al2o3 (multi-layer) -ticn coating designed for this brand is applied, and the coating surface is smoothed, which improves the ability to resist abrasive wear, spalling and chip build-up. Pc9530 of Korloy company in Korea is a brand of milled stainless steel, which adopts ultra-fine particle matrix and PVD coating

(2) pay attention to the optimal combination of substrate and coating in the development of new brands

for the brands suitable for high-speed machining, the substrate should have high resistance to plastic deformation, cobalt rich surface and crescent wear resistant coating; For grades suitable for intermittent cutting, both the substrate and the coating should have good toughness. Sandvik's special grades gc3205, gc3210 and gc3215 for turning cast iron are CVD coated cemented carbides, which are respectively used for high-speed machining of gray cast iron, high-speed machining of nodular cast iron and intermittent cutting of various cast iron at medium and low speeds. These three grades adopt different hard alloy substrates and Al2O3 and MT TiCN coatings of different thicknesses. The grades of uc5105 and uc5115 cemented carbide CVD coatings for turning cast iron developed by Mitsubishi comprehensive materials Co., Ltd. in Japan, the former is used for high-speed continuous cutting of gray cast iron or nodular cast iron, using a high hardness matrix, while the latter is used for processing nodular cast iron under unstable conditions, using a strong and tough matrix; Both are coated with fine Al2O3 and fine and fibrous TiCN thick films. Casttec lc620h, the turning cast iron brand of boehlerit company of Lanqi group, adopts a strong and tough matrix, which can be used for intermittent cutting. The surface coating of Al2O3 can reduce the wear of crescent pits, and there is an interlocking intermediate layer below to improve the bonding strength, which can process gray cast iron at a high speed of 400m/min

1.2 in terms of superhard tool materials

with the development of dry cutting and hard cutting, in recent years, foreign companies have introduced new brands of ceramics and superhard tool materials, such as ky4400 ceramic blade of Kennametal company, which is a mixed ceramic material suitable for hard turning μ TiCN hard material is added to the Al2O3 matrix with grain size of m to improve the hardness and toughness of the blade. It is suitable for quenching steel or cast iron with hardness of 40 ~ 67hrc in finish or semi finish turning. Ct5005 nickel free cermet turning blade of Sandvik company is a new brand for ultra precision machining, which is suitable for high-efficiency dry cutting or wet cutting. Iscar has introduced two kinds of 908 and 907 grades of ultra-fine particle cemented carbide matrix with PVD TiAlN coating. The former has high resistance to plastic deformation and is suitable for drilling blades and threading blades; The latter is suitable for low and medium speed machining of heat-resistant alloys, austenitic stainless steels and hardened steels

2. Significant progress has been made in tool coating technology

advanced coating equipment has created important conditions for the development of coating technology, especially the PVD coating technology. On the one hand, comprehensive progress has been made in key technologies such as improving control technology, increasing plasma density, increasing magnetic field strength, improving the shape of cathode target, and realizing computer full-automatic control of the process, so that the bonding strength between the coating and the substrate The performance of the coating has been significantly improved. For example, the multi arc coating process and equipment adopted by PLATIT and PVT can effectively control the "droplet" generated by the arc, and greatly improve the surface finish of the tool coating. The cc800/9 coating equipment developed by cemecon company adopts magnetron sputtering technology to fundamentally avoid the "droplet" problem of multi arc process. In order to solve the defects of low deposition rate and low adhesion of magnetron sputtering, it has developed his (high ionization sputtering) technology and h.i.p (high ionization pulse) technology on this basis, Supernitrides series coatings which can simultaneously possess the chemical stability of oxide coatings and the physical properties of hard coatings are introduced. On the other hand, the varieties of coatings have also rapidly expanded from conventional tin, TiCN, TiAlN to special TiAlN, AlTiN, tialcn, CrN, CBC (DLC) coatings, as well as various composite coatings and nano coatings, and can control and change the composition, percentage and structure of the coatings in a wider range to adapt to different processed materials and different cutting conditions, thus significantly improving the cutting performance of the tools. For example, the CrAlN coating of Balzers uses Cr element instead of Ti element. It has high performance of 3200hv hardness and 1100 ℃ oxidation temperature. Compared with TiAlN, it has better toughness and is more suitable for intermittent cutting such as milling and hobbing. Nine kinds of coatings developed by Hitachi are self-contained systems. In addition to conventional tin, TiCN and TiAlN, coatings with Si element instead of Al element are also developed. There are TiSiN coatings suitable for hard cutting; For CrSiN coating with lubricity, adding Si to CR makes the coating finer and further reduces the friction coefficient, which is more suitable for the processing of aluminum, stainless steel and other materials with strong adhesion; Alcrsin coating with super oxidation resistance and tibon coating with low friction coefficient at high temperature. Futuna nano and Futuna top, developed by Balzers and applied by some tool manufacturers, are two TiAlN nanostructure coatings, with a coating hardness of 3300hv and an initial oxidation temperature of 900 ℃. The development, popularization and application of nano coatings will further improve the efficiency of machining

at the same time, in order to improve the efficiency of processing non-ferrous and non-metallic materials such as aluminum alloy, diamond coating has been further applied, and the products cover indexable tools and integral cemented carbide tools. Xiamen Jinlu special materials Co., Ltd. has developed diamond coated solid carbide ball end mills with imported Balzers. OSG company has developed a diamond coated milling cutter with ultrafine particle crystallization, and the crystal particle size is 1 μ m. It makes the cutting edge of the tool sharper, reduces the adhesion in cutting, and reduces the roughness of the workpiece surface

in addition, improving the surface finish of the coating is also a trend in the development of coating technology. The improvement of the anti friction and anti adhesion ability of coated tools is introduced in detail with the back door and tail support pressure testing machine. In the CVD coating, the surface of the coating is smooth through the grain refining technology. For example, the ybd052 black diamond blade used by Zhuzhou Diamond Company for the finishing of cast iron is coated with fine-grained Al2O3, and the blade appearance is bright and smooth. The UE series CVD coated cemented carbide blades of Mitsubishi Corporation for processing steel adopt smooth alumina and smooth coating technology to smooth the fine alumina, that is, the upper layer is coated with a special titanium compound deposition layer, which has smooth surface structure and good chemical stability, and reduces the tool bonding wear. GS coating developed by bueryue company of Japan for GS end milling cutter adopts smoothing technology, and the roughness of coating surface ra=0.08 μ m,Rz=1.1 μ m. The characteristics of the coating surface are significantly improved

3. End mills, taps, drill bits and other traditional tools have entered the development stage of high-speed cutting

for a long time, end mills, taps and drill bits belong to a large number of general-purpose tools, which are mainly made of high-speed steel, with low cutting efficiency. In recent years, due to the improvement of the properties of tool materials, especially ultra-fine cemented carbide materials, the popularization of application, and the continuous progress of coating technology and tool NC grinding technology, the general tools have undergone fundamental changes

firstly, the performance of the overall carbide milling cutter has been doubled, and the cutting speed has been increased from less than 100m/min to more than 180m/min. Especially in the processing of aluminum alloy in the aviation industry, the cutting speed has reached 2000 ~ 5000m/min, which has the level of high-performance tools. Secondly, the variety of integral cemented carbide tools has increased, covering many varieties such as end mills, fried dough twist drills and taps, and the application field has been further expanded. The third is the wide application and popularization of CNC tool grinding machines, which has made great changes in the structure of tools. Theoretically, the five axis CNC tool grinding machines used by tool manufacturing enterprises can process almost any shape of tools, so that the geometry, parameters and tool structure of tool cutting parts break through the old pattern of traditional standard tools, and realize diversified The innovative design that fully reflects the inherent law of the cutting process has fully tapped the potential of general-purpose tools. This significant development of general-purpose tools marks that the development of traditional general-purpose tools such as end mills, taps and drills has entered a new stage of high-speed cutting

4. New development of indexable cutting tools

with the rapid development of manufacturing industry, key industrial departments such as automobile industry, aerospace industry and mold industry have continuously put forward higher requirements for cutting processing. CA still needs a sufficient range of specimen cross-section to characterize the structural characteristics. D/CAM technology and CNC numerical control manufacturing technology are widely used in cutting tools

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