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Mechanical manufacturing technology has developed rapidly from the two aspects of improving precision and productivity. In terms of increasing productivity, increasing the degree of automation is the direction that countries are committed to developing, and in recent years, MCN C to CIMS has developed rapidly and has been applied within a certain range. From the aspect of improving precision, from precision machining to ultra-precision machining, this is also the direction of development of major developed countries in the world. Its precision is from micron to submicron, and even nanometer, and its application range is becoming more and more extensive, and it is widely used in high-tech fields, military industry and civil industry. Such as laser fusion systems, very large-scale integrated circuits, high-density disks, precision radars, missile fire control systems, inertial gyro, precision machine tools, precision instruments, video tape head, copier drum, gas stove valve, etc. must be used Precision machining technology.

With the development of precision machinery and electronic technology, modern products are becoming more and more sophisticated. For example, ultra-large scale integrated circuits require the integration of hundreds of thousands of components on the 1mf plane, the line width is only 1μm, and the shape and position errors are less than 0.05μm °. Therefore, higher requirements are put forward for the corresponding machine tool accuracy, and effective measures must be taken to ensure the processing requirements.

According to the technical research of relevant data, the current level of precision machining is: the dimensional tolerance is not too dry 0.5 ~ 1μm, the shape tolerance is not more than 0.01μm, and the surface roughness Ra is not more than 0.01μm. The machine tools used are: precision milling machine, precision grinding machine, optical lens precision grinding machine, precision gem grinding machine, ultra-precision grinding machine, etc. The parts of the machine tool are dynamic and hydrostatic bearings and guide rails, elastic guide rails, ball or roller preloaded oil-containing bearings and guide rails. The tools and materials used are grinding and diamond, etc. The control system is generally a DC servo motor (DC) one-to-half closed type, with encoder optimal control, logic control or precision DC service motor one-to-one closed loop, and adaptive control is realized by microcomputer.

At present, manufacturing technology has been one of the important means of a country's economic development, many developed countries attach great importance to the level of manufacturing technology and the development of its use for product innovation, expand production and improve international economic competitiveness. The development of manufacturing technology is the main direction and strategic decision for the development of the national economy of all countries in the world. At the same time, it is also a long-term plan for a country to be independent, prosperous and strong, and sustainable and stable economic development. At present, the level of precision and special processing technology is one of the important signs of a country's manufacturing I industry level. Precision machining can achieve the accuracy, surface roughness, processing size range and geometry is an important symbol of a country's manufacturing technology level-precision and special processing technology has become the key to the success of international competition, the development of cutting-edge technology, the development of national defense industry, the development of microelectronics industry, all need precision and special processing technology to build related instruments and equipment.

2 precision machining method

According to the mechanism and characteristics of processing, precision machining can be divided into four categories: tool cutting, abrasive processing, special processing and compound processing.

With the development of processing technology, there are many new processing mechanism, so in precision machining, especially in micro machining. According to the forming mechanism and characteristics of parts. It is divided into three categories: removal processing, combined processing and deformation processing. To processing, also known as separation processing, is the use of force, heat, electricity, light and other processing methods to remove-part of the material from the workpiece, such as cutting, grinding, electrical processing and so on. Combined processing is the use of physical and chemical methods on the surface of the workpiece attachment (deposition), injection (infiltration), welding a layer of different materials, such as electroplating, vapor deposition, oxidation, carburizing, bonding, welding, etc. Deformation processing is the use of force, heat, molecular motion and other means to deform the workpiece, change its size, shape and performance, such as casting, forging and so on. It can be seen that the concept of processing has broken through the traditional means of removal processing, with accumulation, growth, deformation and other characteristics, while emphasizing the surface treatment, forming a surface processing technology. 3 precision machinery (cutting) processing technology and process advantages

Precision machinery (cutting) processing and chip-free process compared to the advantages of cutting, first of all, both high material removal rate, but also good economy. For example, compared with laser plasma processing technology, this is because this process can only achieve a high material removal rate with a large supply of energy. On the other hand, whether the processed workpiece can meet the requirements of size and shape accuracy is still a problem. Chips-free pressure machining is mainly used in mass production, often requiring subsequent cutting to obtain the final qualified workpiece shape. Therefore, the main advantage of mechanical (cutting) processing is to enable the workpiece to achieve higher accuracy.

Precision machining is widely used, especially with the trend of producing tendons in small batches, the shape and size accuracy of the workpiece is increasingly high, which opens up a new and more extensive field for machining. It is natural to use lathes for various turning processes, but it should also be noted that the processing processes such as drilling, milling, grinding and gear cutting can be concentrated on the trend of completing (process integration) on the lathe, which is the processing method of the composite machine tool of the turning and milling center developed now. 4 content of precision machining

The technical difficulty of precision machining is large, the influencing factors are many, the scope is wide, the investment intensity is large, the product personality is strong, its main content has the following five aspects:

(1) In addition to the precision of traditional processing methods, non-traditional processing (special processing) methods have developed rapidly. At present, the traditional processing methods are mainly diamond tool precision cutting rigid, disc rigid stone micro-powder grinding wheel precision grinding, precision high-speed cutting and precision abrasive belt grinding, etc.; non-traditional processing methods are mainly electron beam, ion beam, laser beam and other high-energy beam processing, EDM, electrochemical processing, lithography (etching) and so on. And a composite processing mechanism of electrolytic grinding, magnetic grinding, magnetic fluid polishing, ultrasonic honing and other composite processing methods. The study of machining mechanism is the theoretical basis of precision and ultra-precision machining and the growing point of new technology.

(2) The processed materials processed by precision machining have strict requirements on chemical composition, physical and mechanical properties, chemical properties and processing performance. They should have uniform texture, stable performance and no macro and micro defects inside and outside. The processed materials that meet the performance requirements can obtain the expected effect of precision machining.

(3) processing equipment and process equipment precision machining should have high precision, high stiffness, high stability and automation of the machine tool, the corresponding diamond tool, cubic boron nitride tool, diamond grinding wheel, cubic nitride Hu grinding wheel. And the corresponding high-precision, high stiffness fixtures and other process equipment, in order to ensure the processing quality.

Precision machining should first consider to have the corresponding precision precision machining machine tools, many precision machining is often from the design and production of its ultra-precision machine tools began. And to configure the required tool. At present, the general-purpose series of precision machining machine tools are less. The batch will not be big either. Precision machinery machine tool cost is very high, need special order, if the existing precision machining machine tool processing can not meet the requirements. The machining accuracy can be improved by process measures or error compensation.

(4) Inspection precision machining must have the corresponding inspection technology, Weihai Huashun Precision Machinery Co., Ltd. in the formation of processing and testing integration. There are three methods for precision machining inspection: off-line inspection, in-place inspection and on-line inspection. Off-line inspection refers to sending the workpiece to the inspection room for inspection after the processing is completed. In-situ inspection means that the workpiece is not unloaded after being processed on the machine tool and is inspected on site. If any problems are found. It is easy to process again, and on-line detection is carried out in the process of adding I, so that dynamic error compensation can be actively controlled and implemented.

Error compensation is an important measure to improve the machining accuracy, which is based on the accuracy of machine tool manufacturing has reached a certain level. The influence error is separated, and the error value is compensated by the error compensation device. The static error compensation is based on the error value in advance, in the processing by hardware or software compensation, such as machine tool transmission screw pitch error can be compensated by correcting the ruler.

The on-line inspection and compensation technology of precision machining is the key technology of precision machining to achieve quality assurance. The inspection technology is integrated into the content of precision machining, and the online measurement method can enable the operator to find the problems of the workpiece in time and feed them back to the numerical control system. According to sample survey, at present, the economic loss caused by product quality problems in our country, such as waste products, defective products, reworked products, etc., is about 10% ~ 15% of the output value. The most direct economic benefit of online measuring technology applied to precision machining lies in saving working hours and improving the measuring accuracy. Moreover, due to the use of the function of the machine tool numerical control system, the numerical control system can get the feedback information from the inspection system in time, so that the system error and random error can be corrected in time to change the movement number at the end of the machine, better guarantee the processing quality, promote the development of the integration of processing and measurement, and ensure the sound development of precision machining.

(5) Working environment Precision machining requires working in a certain environment to achieve the technical parameters in precision and surface quality. The conditions of the working environment mainly include temperature, humidity, purification, anti-vibration and other requirements, and sometimes there are special requirements for noise, light, static electricity, electromagnetism, radiation and so on. 5 status of precision machining tasks

The development of China's precision machinery plus I technology is of great significance to China's mechanical institutions and manufacturing.

In terms of design, the popularization of computer-aided design (CAD) technology o Computer-aided design (CAD) technology is an important part of electronic information technology. It is a key high-tech that promotes the development and transformation of scientific research results, promotes the renewal and transformation of traditional industries and disciplines, realizes design automation, enhances the competitiveness of enterprises and their products in the market, and accelerates the development of the national economy and the modernization of national defense, it is also an important technical basis for the further development of computer integrated manufacturing (CIMS). The precision machining blog pointed out that the wide application of CAD technology has improved the design level and product development capabilities of Chinese enterprises. Focusing on two-dimensional CAD and product data management, it has been fully utilized in the software market and enterprise applications.

In the application, the rapid development of various high-tech, and achieved remarkable results. It is mainly manifested in the following aspects: rapid prototyping manufacturing technology has moved from the beginning to maturity, and its application has begun to take shape; the level of precision forming and precision machining technology has been significantly improved, and it has been widely used in auto parts and major assembly manufacturing; thermal processing The simulation and optimization technology has made important progress, making the thermal processing of materials from "technology to" science "; laser processing has made substantial progress in basic research and technology development, industrial application has achieved economic benefits, numerical control technology has made important progress, and the domestic market share has increased; fieldbus intelligent instrument research and development has made important progress, and the application has a certain foundation; modern integrated manufacturing system research and application has made breakthroughs, and has occupied a seat in the world.

In terms of management, the research and practice of the new production model has its own characteristics, which promotes the technological progress and management modernization of China's manufacturing industry. According to the precision machining blog, through learning and introducing the management experience of industrial developed countries, adopting computer management, paying attention to the renewal and development of organization and management system and production mode, new management ideas and technologies such as just-in-time production (JID), agile manufacturing (AM), lean production (LP) and concurrent engineering (CE) have been introduced, by streamlining the organization, reducing the level of management and eliminating all kinds of waste, the operating efficiency of the enterprise has been significantly improved.

Technology has been greatly developed in precision machining, and precision machining has made the manufacturing process more efficient, so that our production and development will enter a virtuous cycle mode. 6 Precision machining future development forecast

In the past two years, the machinery manufacturing industry is developing at a rapid pace to precision machining and ultra-precision machining. In the future development process, precision machining and ultra-precision machining will become the key technology to win in international competition and market competition. The development of modern manufacturing industry is committed to improving processing accuracy. The main reason is to improve the performance and quality of products, improve the stability and reliability of their quality, and promote the miniaturization and functionality of products. Good interchangeability, high productivity in product assembly and debugging, and promote manufacturing and assembly automation.

With the development of the manufacturing industry, the current precision machining is developing from micron and sub-micron technology. In the future processing, the precision of ordinary machining, precision machining and ultra-precision machining can reach 1 m, 0.01μm and 0.001μm (I .e. 1nm) respectively, and the ultra-precision machining is pressing into the atomic-level machining precision (0.1nm). With the continuous improvement of extreme machining accuracy, it has created conditions for the development and progress of science and technology, and also provided a good material means for mechanical cold processing.