Development of cutting tool coating technology at home and abroad (5)

Suggestions <br> <br> With the development of China's automotive, aviation, aerospace, heavy machinery and other industries as well as the rapid spread of CNC machine tools, machining of high-speed machining technology is moving in the direction of the development of green manufacturing, high-speed hobbing, The application of high-speed milling and dry cutting processes places higher demands on tool coating technology. Taking gear high-speed hobbing as an example, the advanced process requires the use of the HoS2 soft coating technology of the hob. Compared with the TiN coating, the service life can be more than doubled. In high-speed milling, carbide milling tools are mostly TiAlN, TiAlCN or TiNAlN coatings, and a single TiN coating is not suitable for such processing. Market demand has forced domestic countries to accelerate the research and development of new PVD technologies.

The author believes that in order to achieve rapid and orderly development of China's new PVD coating technology, efforts should be made to do the following:

(1) Strengthening the planning and management tools of the project The industry management department should strengthen the planning and management of PVD coating projects, clarify the short, medium and long-term development goals of China's new PVD coating technology, and establish a planned and uninterrupted development policy. And through the organic combination of "official, production, learning, research, business", the project has both policy support and financial support. China has also had successful experience in this respect: in the mid-eighties, in order to build on the basis of the introduction and improve the overall level of coating technology in the tool industry, the former Machine Tool Division of the Ministry of Machinery Industry organized the whole industry to introduce equipment. The technical research and development of the hot cathode arc magnetron plasma coating machine has been successfully promoted and applied in the tool industry, and thus led to the popularization of domestic TiN coating tools.

(2) Establish a unified research, development, and service system to establish a unified research, development, and service system. According to the development trend of coating technology and domestic and international market demand, systematically introduce international advanced technology and strengthen the digestion and absorption of imported technologies. And collaborative research work, gradually enhance self-development capabilities, form patented technology, and ultimately achieve the purpose of meeting domestic market demand and participating in international market competition.

(3) Establish industry standards for tool coating technology Establish industry inspection standards for coating equipment and coating tools, strictly control coating tool quality, and ensure large-scale application and application of coating technology. Source of information: Tool technology Cutting tool surface coating technology is a material surface modification technology developed in recent decades in response to market demand. The coating technology can effectively improve the service life of the cutting tool, and the tool can obtain excellent comprehensive mechanical properties, thereby greatly improving the machining efficiency. Therefore, coating technology together with materials and cutting processes is called the three key technologies in the field of cutting tool manufacturing. In order to meet the requirements of modern machining for high efficiency, high precision and high reliability, the manufacturing industry in the world has paid more and more attention to the development of coating technology and its application in tool manufacturing. After years of development, China's tool coating technology is currently in a critical period, that is, the original technology can no longer meet the increasing requirements of cutting processing, and the coating equipment of major domestic tool factories has reached a period of renewal. Therefore, fully understand the current status and development trend of tool coating technology at home and abroad, aim at the advanced level of international coating technology, and develop tool coating technology (especially PVD technology) in a planned and step-by-step manner to improve the manufacturing level of cutting tools in China. Significance. Tool coating technology can be divided into chemical vapor deposition (CVD) technology and physical vapor deposition (PVD) technology, which are reviewed as follows.

Foreign CVD technical development <br> <br> since the 1960's, CVD technique is widely used in surface treatment of carbide indexable cutting tools. Since the preparation of the metal source required for vapor deposition in the CVD process is relatively easy, deposition of single-layer and multi-layer multi-layer composite coatings such as TiN, TiC, TiCN, TiBN, TiB2, Al2O3, etc. can be realized, and the bonding strength between the coating and the substrate is high, and the film is high. Thickness can reach 7 ~ 9μm, so by the middle and late 1980s, 85% of cemented carbide tools in the United States used surface coating treatment, of which CVD coating accounted for 99%; by the mid-1990s, CVD coating Carbide inserts still account for more than 80% of coated carbide tools. Although the CVD coating has good wear resistance, the CVD process has its own defects: First, the processing temperature is high, which tends to cause the bending strength of the tool material to decrease; secondly, the inside of the film is in a tensile stress state, which is easy to cause the tool to be used. Microcracks are generated when the CVD process emits exhaust gas and waste liquid, which is in conflict with the current green manufacturing concept. Therefore, since the mid-1990s, the development and application of high temperature CVD technology has been limited. Restricted.

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