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Look at the following may be a little useful to you! 1
What is CNC
Numerical control technology refers to the use of digital instructions composed of numbers, words and symbols to achieve one or more mechanical equipment movement control technology. It controls usually mechanical quantities such as position, angle, speed and switching quantities related to the flow of mechanical energy. Numerical control depends on the emergence of data carriers and binary forms of data operations. 1908, perforated metal sheet interchangeable data carriers were introduced; the end of the 19th century, paper as a data carrier and auxiliary functions of the control system was invented; 1938, Shannon in the U.S. Massachusetts Institute of Technology carried out a rapid calculation and transmission of data, laying the foundation for modern computers, including computer numerical control systems. Foundation. CNC technology is closely integrated with the development of machine tool control. 1952, the first CNC machine tool was introduced, becoming an epoch-making event in the history of the world's machinery industry, promoting the development of automation.
Now, CNC technology is also called computer numerical control technology, it is currently the use of computers to achieve digital program control technology. This technology uses a computer to perform the control function of the equipment according to the control program stored in advance. As a result of the use of computers to replace the original hardware logic circuits composed of numerical control devices, so that the input data storage, processing, arithmetic, logic judgment and other control functions can be achieved through computer software to complete.
Numerical control machine tool is a technology-intensive and high degree of automation of mechatronics processing equipment, is a comprehensive application of computers, automatic control, automatic detection and precision.... High processing accuracy, quality is easy to ensure that the development prospects are very broad, so it is particularly important to master the CNC lathe processing programming technology
The development trend of CNC machine tools
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April 19 from the seventh China International Machine Tool Show was informed that, with the continuous development of science and technology, the development of CNC machine tools is also getting faster, CNC machine tools are also moving towards high-performance, high-precision, high-speed, high flexibility and modularity direction. High performance: With the enhancement of the integration of CNC systems, CNC machine tools also realize multiple centralized control, and even remote control over long distances. High precision: the precision of the CNC machine tool itself and the precision of the processed parts is getting higher and higher, and the precision should be well maintained. High speed: the speed of each axis of CNC machine tool operation will be greatly accelerated. High flexibility: the flexibility of CNC machine tools will be developed in the direction of a higher degree of automation, management, logistics and the corresponding auxiliary machine integrated flexible manufacturing system. Modular: CNC machine tools to shorten the cycle and reduce costs, it is inevitable to the direction of modular development, which is beneficial to both manufacturers and customers. Although China's rapid development of CNC machine tools in recent years, but with the international advanced level there is still a certain gap, mainly in: poor reliability, poor quality appearance, long product development cycle, poor strain capacity. In order to narrow the gap with the world's advanced level, experts suggest that machine tool companies should focus on the following six aspects of research: 1) Increase efforts to implement quality projects to improve the failure rate of CNC machine tools. 2) Tracking the international level, so that the CNC machine tools to the development of high-efficiency and high-precision. 3) Increase the complete set of design and development capabilities to seek breakthroughs. 4) Give play to the advantages of the service, to expand market share. 5) Multi-multi-species manufacturing to meet the different levels of users. 6) The development of the CNC machine tool industry in the world. Meet different levels of users. 6. Modular design, shorten the development cycle, rapid response to the market. CNC machine tools are used more and more, the domestic and international market capacity is also growing, but the competition will intensify, we can only keep up with the general direction of the progress of advanced technology and continuous innovation in order to catch up with the world's advanced level. Metallurgical Newspaper of China
The development trend of CNC technology and equipment and countermeasures
1 The development trend of CNC technology
The application of CNC technology not only to the traditional manufacturing industry has brought about revolutionary changes to the manufacturing industry has become a symbol of industrialization, but also with the continuous development of CNC technology and the expansion of the field of application, he was on the national economy and people's livelihood of a number of important industries (it, automotive, The development of some important industries (it, automotive, light industry, medical, etc.) plays an increasingly important role, because these industries need to digitize the equipment has been a major trend of modern development. From the world's current trends in the development of CNC technology and its equipment, its main research hotspots are the following aspects [1 to 4].
1.1 high-speed, high-precision machining technology and equipment for the new trend
Efficiency, quality is the main body of advanced manufacturing technology. High-speed, high-precision machining technology can greatly improve efficiency, improve product quality and grade, shorten the production cycle and improve market competitiveness. For this reason, Japan's Advanced Technology Research Institute will be listed as one of the five modern manufacturing technology, the International Production Engineering Society (cirp) will be identified as one of the central research direction of the 21st century.
In the field of car industry, the annual output of 300,000 production beat is 40 seconds / vehicle, and multi-species processing is one of the key issues that car equipment must be resolved; in the field of aviation and aerospace industry, the processing of parts and components are mostly thin-walled and thin tendons, stiffness is very poor, the material for the aluminum or aluminum alloy, only in the case of high cutting speeds and cutting force is very small in order to be able to process these tendons and walls. Recently, the use of large whole aluminum alloy billet "hollowing" method to manufacture wings, fuselage and other large parts to replace multiple parts through a large number of rivets, screws and other joints assembled, so that the strength, stiffness and reliability of the component has been improved. These are on the processing equipment put forward high-speed, high-precision and highly flexible requirements.
From the situation of emo2001 exhibition, high-speed machining center feed speed up to 80m/min, or even higher, empty running speed up to about 100m/min. At present, many automobile factories in the world, including China's Shanghai General Motors, has been used to high-speed machining centers composed of the production line partially replaces the combination of machine tools. The United States cincinnati company's hypermach machine tool feed speed up to 60m/min, fast for 100m/min, acceleration up to 2g, the spindle speed has reached 60 000r/min. Processing of a thin-walled aircraft parts, only 30min, and the same parts in the general high-speed milling machine processing needs 3h, in the ordinary milling machine processing needs 8h; Germany dmg The company's dual spindle lathe spindle speed and acceleration were up to 12 *!000r/mm and 1g.
In terms of machining accuracy, in the past 10 years, the machining accuracy of the general level of CNC machine tools has been increased from 10μm to 5μm, precision level machining centers from 3 ~ 5μm, to 1 ~ 1.5μm, and ultra-precision machining accuracy has begun to enter the nanometer level (0.01μm). m).
In terms of reliability, foreign CNC devices mtbf value has reached more than 6,000h, servo system mtbf value of more than 30,000h, showing very high reliability.
In order to realize high-speed, high-precision machining, and its supporting functional components such as electric spindle, linear motors have been rapid development, the application field is further expanded.
1.2 5-axis linkage machining and the rapid development of composite processing machine tools
The use of 5-axis linkage on the processing of three-dimensional curved parts, the best geometry of the available tool cutting, not only high finish, but also a substantial increase in efficiency. It is generally believed that the efficiency of a 5-axis linkage machine tool can be equal to 2 3-axis linkage machine tool, especially the use of cubic boron nitride and other super-hard materials such as milling cutter for high-speed milling hardened steel parts, 5-axis linkage machining can be compared to 3-axis linkage machining to play a higher benefit. But in the past, because of the 5-axis linkage CNC system, the host structure is complex and other reasons, its price is several times higher than the 3-axis linkage CNC machine tools, coupled with the programming technology is more difficult, restricting the development of 5-axis linkage machine tools.
Currently due to the emergence of electric spindle, making the realization of 5-axis linkage machining composite spindle head structure is greatly simplified, its manufacturing difficulties and costs have been significantly reduced, the price gap between the CNC system to narrow. Therefore, promote the composite spindle head type 5-axis linkage machine tools and composite processing machine tools (including 5 surface machining machine tools) development.
In the emo2001 exhibition, the new nippon koki's 5 face machining machine tool with composite spindle head, can realize 4 vertical plane machining and any angle machining, make 5 face machining and 5 axis machining can be realized in the same machine tool, but also can realize inclined plane and inverted taper hole machining. Germany dmg company exhibits dmuvoution series machining center, can be in a clamping under the 5 surface machining and 5-axis linkage machining, can be controlled by cnc system control or cad/cam direct or indirect control.
1.3 Intelligent, open, networked to become a major trend in the development of contemporary CNC systems
21st century CNC equipment will be a system with a certain degree of intelligence, the content of intelligence, including all aspects of the CNC system: for the pursuit of machining efficiency and quality of machining intelligence, such as adaptive control of the process of machining, the automatic generation of process parameters; in order to improve the drive Performance and the use of convenient connection of intelligence, such as feed-forward control, adaptive operation of motor parameters, automatic load recognition automatically selected model, self-tuning, etc.; simplify the programming, simplify the operation of intelligence, such as intelligent automatic programming, intelligent human-machine interface, etc.; there are also intelligent diagnostics, intelligent monitoring of the contents of the system to facilitate diagnostics and maintenance, etc..
In order to solve the traditional closed CNC system and CNC application software industrialized production problems. At present, many countries on the open CNC system research, such as the United States of ngc (the next generation work-station/machine control), osaca of the European **** body (open system architecture for control within automation systems), Japan's osec (open system environment for controller), China's onc (open numerical control system) and so on. CNC system openness has become the future of the CNC system. The so-called open numerical control system is the development of numerical control system can be in a unified operating platform for machine tool manufacturers and end-users, by changing, increasing or tailoring the structure of the object (numerical control function), the formation of a series, and can be easily integrated into the control system of the user's special applications and know-how, the rapid realization of different varieties of open numerical control system of different grades, the formation of a distinctive personality of the Famous brand products. At present, the open CNC system architecture specification, communication specification, configuration specification, operation platform, CNC system function library and CNC system function software development tool is the core of the current research.
Networked CNC equipment is a new highlight of the international famous machine tool exposition in the past two years. Networking of CNC equipment will greatly meet the production line, manufacturing system, manufacturing enterprises on the demand for information integration, but also the realization of new manufacturing models such as agile manufacturing, virtual enterprises, global manufacturing base unit. Domestic and foreign some famous CNC machine tools and CNC system manufacturing companies have in the past two years launched the relevant new concepts and prototypes, such as in the emo2001 exhibition, Japan's Yamazaki Mazak (mazak) company exhibited the "cyberproduction center" (intelligent production control center, referred to as the cpc); Japan's Okuma (okuma) machine tool company exhibited "it plaza" (information technology plaza, referred to as it square); Germany's Siemens (siemens) company exhibited open manufacturing environment (open manufacturing environment, referred to as ome), etc., reflecting the digitalization of the machine tool industry. ome), reflecting the trend of CNC machine tool processing to the direction of network development.
1.4 Emphasis on the establishment of new technology standards, norms
1.4.1 On the CNC system design and development specifications
As mentioned earlier, the open CNC system has a better versatility, flexibility, adaptability, scalability, the U.S., the European **** body and Japan have to implement the strategic development plan, and open architecture CNC system specification (omac) , osaca, osec) research and development, the world's three largest economies in a short period of time to carry out almost the same scientific program and the development of norms, heralding the advent of a new period of change in numerical control technology. China in 2000 also began to carry out China's onc CNC system specification framework research and development.
1.4.2 About CNC standards
Numerical control standards are a trend in the development of manufacturing information technology. CNC technology after the birth of 50 years of information exchange are based on iso6983 standard, that is, the use of g, m code describes how to (how) processing, its essential feature is oriented to the processing process, obviously, he has been increasingly unable to meet the needs of the rapid development of modern CNC technology. To this end, the international research and development of a new cnc system standard iso14649 (step-nc), its purpose is to provide a neutral mechanism that does not depend on the specific system, can describe the product throughout the life cycle of the unified data model, so as to achieve the entire manufacturing process, and even the standardization of product information in various industrial areas.
The emergence of step-nc may be a revolution in the field of numerical control technology, for the development of numerical control technology and even the entire manufacturing industry, will have far-reaching impact. First of all, step-nc puts forward a brand new manufacturing concept, the traditional manufacturing concept, nc machining program are concentrated in a single computer. And in the new standard, nc program can be dispersed on the Internet, which is the direction of open, networked development of CNC technology. Secondly, step-nc CNC system can also greatly reduce the processing drawings (about 75%), processing program preparation time (about 35%) and processing time (about 50%).
At present, Europe and the United States attaches great importance to step-nc research, Europe launched the step-nc ims program (1999.1.1 ~ 2001.12.31). Participating in this program are 20 cad/cam/capp/cnc users, manufacturers and academic institutions from Europe and Japan. The United States of step tools company is the world-wide manufacturing data exchange software developers, he has developed as a CNC machine tool machining information exchange super model (super model), its goal is to use a unified specification describes all the machining process. The goal is to describe all machining processes with a uniform specification. The new data exchange format has already been validated on prototypes equipped with Siemens, Fidia, and European osaca-nc CNCs.
2 Basic estimation of China's CNC technology and its industrial development
China's CNC technology started in 1958, nearly 50 years of development can be roughly divided into three stages: the first stage from 1958 to 1979, that is, the closed development stage. In this stage, due to foreign technology blockade and the limitations of China's basic conditions, the development of CNC technology is relatively slow. The second stage is in the country's "Sixth Five-Year Plan", "Seventh Five-Year Plan" period and "Eighth Five-Year Plan" of the early stage, that is, the introduction of technology, digestion and absorption, the initial establishment of the localization system stage. In this stage, due to the reform and opening up and the country's attention, as well as research and development environment and the improvement of the international environment, China's CNC technology research, development and localization of products have made great progress. The third stage is in the country's "Eighth Five-Year Plan" late and "Ninth Five-Year Plan" period, that is, the implementation of industrialization of research, enter the market competition stage. At this stage, China's domestic CNC equipment industrialization has made substantial progress. In the "Ninth Five-Year Plan" at the end of the domestic market share of domestic CNC machine tools up to 50%, with the domestic CNC system (popularized) also reached 10%.
Looking at the development of China's CNC technology in the past 50 years, especially after four five-year plan of research, in general, the following achievements.
a. laid the foundation for the development of CNC technology, basic mastery of modern CNC technology. China has now basically mastered from the CNC system, servo drive, CNC host, special machine and its supporting parts of the basic technology, most of which have been equipped with the commercialization of the development of the basis of some of the technology has been commercialized, industrialized.
b. Initially formed a CNC industrial base. On the basis of the results of research and commercialization of some of the technologies, the establishment of such as Huazhong CNC, Aerospace CNC and other CNC production plants with mass production capacity. Lanzhou Electric Factory, Huazhong NC and a number of servo systems and servo motor production plants, as well as the first machine tool plant in Beijing, Jinan, the first machine tool plant and a number of CNC host production plants. These production plants have basically formed China's CNC industrial base.
c. The establishment of a basic team of CNC research, development and management personnel.
While the research and development of CNC technology and industrialization has made great progress, but we also need to be soberly aware that China's high-end CNC technology research and development, especially in the industrialization of the current state of the technology level and the reality of China's needs and there is still a large gap. Although from the vertical view of our country's rapid development, but horizontally than (compared with foreign countries) not only the technical level of the gap, in some aspects of the development speed also has a gap, that is, some of the high-precision CNC equipment, the technology level gap has a tendency to expand. From an international perspective, the level of CNC technology in China and industrialization level is estimated roughly as follows.
a. Technical level, and the advanced level of foreign countries about 10 to 15 years behind, in terms of high-precision technology is even greater.
b. Industrialization level, low market share, small variety coverage, has not yet formed a large-scale production; professional production level of functional components and complete sets of low capacity; relatively poor quality of appearance; reliability is not high, the degree of commercialization is insufficient; domestic CNC system has not yet established its own branding, the user's confidence is insufficient.
c. Sustainable development of the ability to pre-competitive CNC technology, research and development, engineering capability is weak; CNC technology applications to expand the strength of the field is not strong; related standards and norms of research, development lag.
Analysis of the main reasons for the existence of the above gap are the following aspects.
a. Recognition. Domestic CNC industrial process of arduous, complex and long-term characteristics of insufficient understanding; market irregularities, foreign blockade plus stranglehold, institutional and other difficulties are underestimated; China's level of application of numerical control technology and the ability to analyze the insufficient.
b.System aspects. From the technical point of view to focus on the industrialization of CNC more often than not, from a systematic, industrial chain point of view of the comprehensive consideration of the industrialization of CNC less often; did not establish a complete high-quality supporting system, perfect training, service network and other support systems.
c. Mechanisms. Adverse mechanisms cause brain drain, but also restricts the technology and technology route innovation, product innovation, and constraints on the effective implementation of planning, often planning ideal, implementation difficulties.
d. Technology. Enterprises in the technical aspects of independent innovation is not strong, the core technology engineering capability is not strong. Machine tool standards are backward, low level, CNC system new standards research is not enough.
3 Strategic thinking on the development of China's CNC technology and industrialization
3.1 Strategic considerations
China is a large manufacturing country, in the world of industrial transfer to try to accept the front-end rather than the back-end of the transfer, that is, to master the core technology of advanced manufacturing, or else in the new round of international industrial structural adjustment, China's manufacturing industry will further " Empty core". We to resources, environment, market as the price, the exchange may only be the world's new economic pattern of international "processing center" and "assembly center", rather than mastering the core technology of the manufacturing center of the status, this will seriously affect our modern manufacturing industry This will seriously affect the development process of China's modern manufacturing industry.
We should stand at the height of national security strategy to pay attention to CNC technology and industrial issues, first of all, from the point of view of social security, because the manufacturing industry is the largest number of employed people in our country, the development of the manufacturing industry not only to improve the people's standard of living, but also alleviate the pressure of employment in our country, to ensure the stability of the community; Secondly, from the point of view of national defense and security, the developed countries in the West to the high-precision and sophisticated CNC products are listed as the national strategic substances, to realize the embargo on our country and the development of the industry. Secondly, from the point of view of national defense security, the western developed countries have classified high-precision CNC products as national strategic substances, and realized embargoes and restrictions on our country, "Toshiba incident" and "Cox Report" is the best example.
3.2 Development Strategy
From the perspective of China's basic national conditions, guided by the country's strategic needs and the market demand of the national economy, and aiming at improving the comprehensive competitiveness and industrialization level of China's manufacturing equipment industry, we use systematic methods to select the key technologies that can dominate the development and upgrading of China's manufacturing equipment industry at the early stage of the 21st century, as well as supporting technologies and complementary technologies to support the development of industrialization. Technology, supporting technology as the content of research and development to achieve the leapfrog development of manufacturing equipment industry.
Emphasis on market demand-oriented, that is, the main CNC end-products, the whole machine (such as a large number of CNC lathes, milling machines, high-speed high-precision and high-performance CNC machine tools, typical digital machinery, key industries, key equipment, etc.) to drive the development of the CNC industry. Focus on solving the reliability and production scale of CNC systems and related functional components (digital servo systems and motors, high-speed spindle systems and new equipment such as accessories). No scale will not have a high reliability of the product; no scale will not have a low price and competitive products; of course, no scale of China's CNC equipment is ultimately difficult to have a head start.
In the research and development of high-precision equipment, to emphasize the close integration of production, learning, research and end-users to "do it, use it, sell it" as the goal, according to the national will to implement the research to solve the country's urgent needs.
In the pre-competitive CNC technology, emphasizing innovation, emphasizing the research and development of technology and products with independent intellectual property rights for China's CNC industry, equipment manufacturing and even the entire manufacturing industry to lay the foundation for sustainable development.