Cutting tool coating technology rapid development, coated tools has been widely applied. 1969, Germany Krupp Krupp company and Sweden Sandvik Sandvik () the company successfully developed chemical vapor deposition (CVD) coating technology, and to market the CVDTiC coating carbide blade products. In the early 1970 s, the United States this summer (R.R unshan) and rakes Hu Na (A.R aghuran) developed a physical vapor deposition (PVD) technology, and in 1981 will PVDTiN HSS cutting tools products to the market. When CVD coating process temperature about 1000 ℃, is mainly used for surface coating cemented carbide cutting tools (blade); PVD coating process temperature is below 500 ℃ and 500 ℃, is mainly used for the surface coating of high speed steel tools. Later, CVD and PVD coating technology rapid development, in such aspects as coating material, coating equipment and technology have made great progress, and developed the multi-layer material of coating technology, make the using performance of the coating knife (blade) had the very big enhancement. PVD coating technology is mainly used for high speed steel cutting tools in the past, and in recent years, with the development of PVD coating technology leap, also successfully used for cemented carbide cutting tools (blade), occupied the half of the cemented carbide coating tools (blade) position. Now, coating HSS cutting tools and carbide cutting tools (blade) is widely used, have accounted for more than 50% of the total tool use.
The superiority of coated tools
In toughness good knife (blade) surface coating on the substrate, the coating has high hardness, high wear resistance, high temperature resistant material of thin layer (such as TiN and TiC, etc.), make the knife (blade) comprehensive, good comprehensive performance. No coating HSS hardness was only about 62-68 HRC (760 ~ 960 hv), the hardness of cemented carbide is only 89 ~ 93.5 HRA (1300 ~ 1850 hv); And after the coating surface hardness can reach more than 2000 ~ 3000 hv.
1) due to surface coating materials of high hardness and wear resistance, and resistance to high temperature. So compared with uncoated tool (blade), coated tools allowed the use of higher cutting speed, so as to improve the machining efficiency; Or can under the same cutting speed, improve tool life.
(2) as coating material and processed materials between the friction coefficient is small, so the coating knife (blade) of cutting force is smaller than the uncoated tool (blade).
(3) with coating knife (blade) processing, parts machined surface quality is better.
(4) because of the coating knife (blade) comprehensive performance is good, so the coating carbide blade has good commonality, a blade coating cemented carbide grades has a wide range of use.
Cutting tool coating technology development and progress
The author repeatedly visited the international machine tool exhibition, collected a lot of information, and listen to the technical report of tool company, to know the development of cutting tool product surface coating technology and progress.
CVD coating technology progress
In the past, the carbide tool surface coating with high temperature chemical vapor deposition (HTCVD) process. In the atmospheric pressure or negative pressure of sedimentary system, the pure H2, CH4, N2, TiCl4, AlCl3, CO2 gas according to the composition of sediment, according to certain proportion evenly mixed, tu in order to have a certain temperature (generally 1000 ~ 1050 ℃) of the surface of the carbide insert, namely in the blade surface deposition of TiC, TiN, TiCN, Al2O3, or their composite coating. Until now, the HTCVD is still the most used technique, except HTCVD and plasma chemical vapor deposition (PCVD) process, it is in the carbide cutting tools (blade) coating on the surface of the another way, because of the coating process with low temperature (700 ~ 800 ℃), so the blade bending strength decreased. Because of TiC and closest to the linear expansion coefficient of substrate material, usually with TiC thin layer coated on the substrate surface, first to besmear outside TiN, Al2O3, such as TiC/TiN and TiC/Al2O3, TiC/TiCN/TiN, etc.
Cutting tool coating technology rapid development, coated tools has been widely applied. 1969, Germany Krupp Krupp company and Sweden Sandvik Sandvik () the company successfully developed chemical vapor deposition (CVD) coating technology, and to market the CVDTiC coating carbide blade products. In the early 1970 s, the United States this summer (R.R unshan) and rakes Hu Na (A.R aghuran) developed a physical vapor deposition (PVD) technology, and in 1981 will PVDTiN HSS cutting tools products to the market. When CVD coating process temperature about 1000 ℃, is mainly used for surface coating cemented carbide cutting tools (blade); PVD coating process temperature is below 500 ℃ and 500 ℃, is mainly used for the surface coating of high speed steel tools. Later, CVD and PVD coating technology rapid development, in such aspects as coating material, coating equipment and technology have made great progress, and developed the multi-layer material of coating technology, make the using performance of the coating knife (blade) had the very big enhancement. PVD coating technology is mainly used for high speed steel cutting tools in the past, and in recent years, with the development of PVD coating technology leap, also successfully used for cemented carbide cutting tools (blade), occupied the half of the cemented carbide coating tools (blade) position. Now, coating HSS cutting tools and carbide cutting tools (blade) is widely used, have accounted for more than 50% of the total tool use.
The superiority of coated tools
In toughness good knife (blade) surface coating on the substrate, the coating has high hardness, high wear resistance, high temperature resistant material of thin layer (such as TiN and TiC, etc.), make the knife (blade) comprehensive, good comprehensive performance. No coating HSS hardness was only about 62-68 HRC (760 ~ 960 hv), the hardness of cemented carbide is only 89 ~ 93.5 HRA (1300 ~ 1850 hv); And after the coating surface hardness can reach more than 2000 ~ 3000 hv.
1) due to surface coating materials of high hardness and wear resistance, and resistance to high temperature. So compared with uncoated tool (blade), coated tools allowed the use of higher cutting speed, so as to improve the machining efficiency; Or can under the same cutting speed, improve tool life.
(2) as coating material and processed materials between the friction coefficient is small, so the coating knife (blade) of cutting force is smaller than the uncoated tool (blade).
(3) with coating knife (blade) processing, parts machined surface quality is better.
(4) because of the coating knife (blade) comprehensive performance is good, so the coating carbide blade has good commonality, a blade coating cemented carbide grades has a wide range of use.
Cutting tool coating technology development and progress
The author repeatedly visited the international machine tool exhibition, collected a lot of information, and listen to the technical report of tool company, to know the development of cutting tool product surface coating technology and progress.
CVD coating technology progress
In the past, the carbide tool surface coating with high temperature chemical vapor deposition (HTCVD) process. In the atmospheric pressure or negative pressure of sedimentary system, the pure H2, CH4, N2, TiCl4, AlCl3, CO2 gas according to the composition of sediment, according to certain proportion evenly mixed, tu in order to have a certain temperature (generally 1000 ~ 1050 ℃) of the surface of the carbide insert, namely in the blade surface deposition of TiC, TiN, TiCN, Al2O3, or their composite coating. Until now, the HTCVD is still the most used technique, except HTCVD and plasma chemical vapor deposition (PCVD) process, it is in the carbide cutting tools (blade) coating on the surface of the another way, because of the coating process with low temperature (700 ~ 800 ℃), so the blade bending strength decreased. Because of TiC and closest to the linear expansion coefficient of substrate material, usually with TiC thin layer coated on the substrate surface, first to besmear outside TiN, Al2O3, such as TiC/TiN and TiC/Al2O3, TiC/TiCN/TiN, etc.
PVD coating technology in super hard material coatings applications
Physics department of wuhan university by dc reaction magnetron sputtering method in the tool surface deposition of carbon nitride (CxNy) superhard coating film, the thickness of only a few microns, hardness can reach 40 ~ 50 gpa. CxNy coating knives can cut black and non-ferrous metal.
The experimental data
The author of coated high speed steel and carbide cutting tools (blade) the cutting performance of the long-term research, have conducted many scientific experiments. This is to introduce some experimental data are as follows:
(1) under the same cutting condition, the service life of the cutter blade coating higher than that of uncoated cutting tool (blade) 3 ~ 5 times. Under the same cutting condition, the knives' service life, the same coating knife cutting speed 20 ~ 30% higher than that of uncoated cutting tool.
(2) in the same cutting condition, the coated tools (blade) of the cutting force is smaller than the uncoated. Using coated TiC carbide insert turning steel compared with uncoated blade, the cutting force Fc can reduce 3% ~ 4%, the TiN and TiC/TiN coating blade Fc can be reduced about 6%, the feed force Ff and deep cutting force is especially significant decrease of Fp. Effect of Al2O3 coating blade with the decrease of cutting force and the TiN coating blade.
(3) the author has used CVD diamond thick film cutting tools coating, processed silicon aluminum alloy, various kinds of hard aluminium, lead brass, oxygen-free copper, titanium iodide and fiber reinforced and particle reinforced composite materials and so on, has achieved good effect. But the tool used for ultra precision cutting, the effect is better than natural diamond cutting tools.
(4) the author has used CxNy coating HSS drill hole in the high strength steel, compared with uncoated bit, coating the service life of bit 7 ~ 9 times. On top of other high speed steel cutter coated CxNy, also have a significant effect. Once again on the carbide blade coating CxNy, to turning steel material, effect is not ideal enough, its service life is less than ordinary TiC coating carbide insert.
Cutting tool coating technology in China compared with industrial developed countries still have large gap, coated tools differ very far, the number of roughly accounted for only 20% of all cutting tools. Which used on CNC machine tools and machining center, in the ordinary course of the little on nc machine tools, reason is known, and the price and other factors. We should strive to improve the level of cutting tool coating technology and application technology, vigorously applied coating cutting tools, promote the machining and the improvement of machinery manufacturing.