1. Introduction to PVD coating technology

 
  Physical vapor deposition (PVD) is a standardized term for surface treatment. It has a wide range of applications from high-precision machining tools, decorative parts, high-demand mechanical parts to molds for high-precision integrated circuits. It is an environmentally friendly surface treatment for PVD films that are truly micron-sized and non-polluting. The method, without affecting the original size of the workpiece, is used to improve the appearance of the surface, improve the strength of the surface, enhance the wear resistance, and has good heat conduction, corrosion resistance and scratch resistance.
 
  PVD technology appeared in the late 1970s and can be used as a final treatment process for the coating of high speed steel tools because its process temperature can be controlled below 500 °C. Since the PVD process can greatly improve the cutting performance of high-speed steel tools, the technology has been rapidly popularized since the 1980s. By the end of the 1980s, the proportion of PVD coatings for high-speed steel complex tools in industrialized countries has exceeded 60%. .
 
2. The status quo of PVD coating technology in China's tool manufacturing
 
  The research and development of PVD coating technology in China began in the early 1980s. In the mid-1980s, the small and medium-sized hollow cathode PVD ion coating machine was successfully developed, and the TiN coating technology of high speed steel tool was developed. During this period, due to the promising prospects for the cutting tool coating market, seven large tool factories in China introduced large PVD coating equipment from abroad. The introduction of technology and equipment mobilized the development boom of domestic PVD technology. Many research institutes and major vacuum equipment factories have started the development of large-scale ion coating machines, and developed a variety of PVD coating equipment in the early 1990s. However, due to the low performance index of most equipment, the quality of the tool coating cannot be guaranteed, and the expected market benefits are not realized. Therefore, most companies have not further studied PVD tool coating technology, resulting in the domestic PVD tool coating for nearly ten years. The development of technology has stalled. Despite the successful development of the hard alloy TiN-TiCN-TiN multi-component coating technology in the late 1990s and the practical level, the development of CNx coating technology has also made a major breakthrough, but compared with the international development level, China's tool PVD Coating technology is still about a decade behind. At present, foreign tool PVD coating technology has been developed to the fourth generation, while the domestic is still in the second generation level, and still dominated by a single layer of TiN coating.
 
3. Problems in the research and application of domestic PVD coating technology
 
   3.1 Does not adapt to changes in the tool coating market The application of coating tools is closely related to the cutting technology. Unlike the 1990s, the current applications are more focused on carbide indexable inserts, high speed gear cutters, and hard alloys. Rod cutters and some special-shaped cutters. For CNC machine tools, the cutting speed is usually higher than 100m/min, and a single TiN film is difficult to meet the requirements. At present, the domestic commercial application of PVD technology is still based on high-speed steel tool coating. Although the demand for coated tools is increasing, for example, the total amount of tool coating processing in Chongqing has increased from 1 million yuan in 2000 to 1000 this year. More than 10,000 yuan, but the application field is still dominated by motorcycle gear processing and other industries, cutting speed is mostly less than 50m / min; and in the field of cemented carbide tools, most of its high-end coated tool products are coated abroad. The monopoly of the company, especially the emergence of foreign tool coating processing service centers, has made domestic coating processing service enterprises face more severe competition.
 
   3.2. Insufficient attention paid to the research and development of new processes. Although the most advanced PVD technology was introduced in the 1980s, PVD technology was still in the early stage of development, and domestic development space and development speed could not be fully estimated. In addition, physical coating Technology is a new technology integrating electronic physics, materials and vacuum control technology. It has high requirements for personnel deployment in research, production and application. Most of the companies that introduce PVD technology focus on production, and developers and funds are allocated. Insufficient, it is difficult to promote the further independent development of process technology, new processes, new technologies still need to be introduced, and the cost of re-introduction is very expensive, thus affecting the development of new coating technology and equipment.
 
   3.3. Problems in the development and manufacture of coating equipment In the late 1980s, domestic vacuum equipment manufacturers and some scientific research units were too optimistic about the PVD tool coating market, and each of them increased the development of various PVD coating equipment, but due to lack of The in-depth understanding of the tool and its coating technology has not strengthened the cooperation with the tool factory. Most of the coating equipment developed cannot meet the requirements of the tool coating process, especially the precision high-speed steel tool coating technology is still not up to Mass production level. Most of these types of equipment can only be used for the coating of twist drills. Due to the extremely low cost of twist drill coating and the low profit of the corresponding coating equipment, most vacuum equipment manufacturers have taken the development direction after entering the 1990s. Turn to other industries (such as decorative coatings, etc.).
 
   3.4. The overall matching is poor. The lack of overall matching of applied basic research and the lack of applied basic research have always been the bottleneck that has plagued the development of domestic tool coating technology. At present, the trend of tool coating is based on the development of coating processing centers, so the integrity of the technology is extremely critical. Pretreatment technology, coating technology, post-processing technology and quality control technology should all be considered. Most of the domestic coating equipment manufacturers only provide coating mainframes, which hinders the rapid advancement of industrial production; on the other hand, it also causes serious disconnection between equipment manufacturers and the market, which restricts the sound development of technology, making Innovation cannot be discussed.
 
   3.5, the instability of coating quality restricts the promotion of coating technology, the high price of imported equipment, resulting in high coating prices, coating costs even exceed 50% of the tool price, in addition to the introduction of different channels The basis of equipment selection is different, which leads to a large difference in the process level of the equipment, which affects the use effect of the coating tool. At the same time, due to the unstable quality of the domestic coating tool, the inspection standard of the coating tool is not complete, so it is caused in the application field. The impression that the coating price is high, but the coating quality is unstable and the tool performance is not obvious, seriously affects the promotion and application of the technology.
 
4. Countermeasures for developing new PVD coating technology in China
 
   4.1. Strengthening the planning and management of the project The industry management department should strengthen the planning and management of the project, clarify the short-, medium- and long-term development goals of China, establish a plan for uninterrupted development, and adopt “official, production, The combination of learning, research and business can make the project supportively in terms of policy and capital. In fact, in the mid-eighties, the Machine Tool Division of the Ministry of Machinery Industry organized the industry-wide efforts to tackle the introduction of PVD coating equipment, and developed the hot cathode arc magnetron plasma coating machine. It has been successfully promoted and applied in the tool industry, and thus has driven the popular application of domestic TiN coated tools.
 
   4.2. Establish research and development of new thinking tool coating technology set materials, preparation methods, vacuum technology, cutting technology in one, both comprehensive and cutting-edge, to achieve sound development, we must establish a reasonable, overall research and development Ideas. From the development of tool coating technology in China for decades, the disconnection of various research links is the crux of restricting its development. The development ideas should follow: market research → film performance research → preparation method research → laboratory device development → application basic research → industrial production equipment design and manufacturing → application process technology research → market assessment, and form a cycle.
 
   4.3. Establish a unified research, development, service system, and industry standards to establish a unified research, development, and service system. According to the needs of domestic and foreign markets, systematically introduce international advanced technologies, and strengthen the digestion and absorption of collaborative technologies and collaborative research. And gradually reach the level of self-development, and ultimately achieve participation in the international market competition.
 
Establish inspection standards for coating equipment and coating tools, strictly control the quality of coating tools, and ensure the wide application of coating technology