Second, the origin of vibration aging:
The vibration aging originated in the European and American countries after World War II. Around the 1950s, with the development of modern science and technology, vibration theory, testing technology and vibration equipment have been rapidly developed. It has been found that vibration at the resonance frequency of the workpiece can shorten the vibration processing time, eliminate the stress and stabilize the precision, and minimize the energy consumption. At the same time, the corresponding vibration equipment appeared. The emergence of this new type of vibration aging process and equipment has been highly valued by countries and quickly applied to production practice.
As this process is becoming more mature, vibration and control equipment are improving day by day, and vibration aging has been widely adopted in more than a dozen industrialized countries. A stress-relieving company in the United States has 350 vibration aging equipment and has performed more than 5,000 vibration aging treatments. In the United Kingdom and West Germany, vibration aging is commonly used for welded beams and frames of aircraft frames. The former Soviet Union Metal Cutting Machine Experimental Science Research Institute recommended the vibration aging process to various machine tool factories. The large parts and basic parts of some heavy machine tool factories all adopt vibration aging.
In the situation of energy shortage and deteriorating ecological environment, the VSR process of high efficiency and energy saving to reduce environmental pollution has been rapidly developed in foreign countries in the past two or three decades. Now the United States, Britain, Germany, France, Russia, Canada, Belgium, Romania, Japan and other countries have been applied to various light and heavy industries such as aviation, ocean, drilling, mining, machine tools, textiles, paper, oil transportation, etc. , forging, weldments and non-ferrous metal parts. The United States, Germany, France, and the United Kingdom all have world-renowned VSR equipment manufacturers.
Third, the application history of vibration aging in China:
Vibration aging (VSR) was introduced to China in the 1970s. In 1974, the Beijing Machine Tool Research Institute officially listed the VSR process as a research topic, and began research work on VSR processes and equipment for machine tool cast iron parts. After several years of research, the basic process of VSR was determined and the VSR effect was confirmed. With the progress and deepening of the research, during the "Sixth and the Fiveth" period, VSR was listed as the key research project of 38 key research projects in China to improve the quality of machine tool castings. The Beijing Machine Tool Research Institute is responsible for the VSR process. Sex research. The research task was completed on schedule, and the “Six and Five†total appraisal, VSR process research reached the world advanced level. “Seventh and Five†Beijing Machine Tool Research Institute has also undertaken the national key project “Research on the vibration aging process of welded components of one-stop CNC machine toolsâ€. After the "seventh and fifth", China's VSR process is mature and complete. VSR equipment has also reached the world's advanced level and basically meets the requirements of VSR process. The “eight and five†VSRs have been listed as one of the “eight and five†six key promotion technologies by the State Science and Technology Commission, the Ministry of Electrical and Mechanical Services and the State Council Production Office. In 1999, the former State Economic and Trade Commission listed it as a national key promotion project; in July 1999, the China Mechanical Engineering Society established the Stress Relief Technical Committee, and China has a national academic organization specializing in stress and deformation; The State Economic and Trade Commission listed the new generation of VSR equipment as a national key technological innovation project; in 2001, the former State Economic and Trade Commission supported the standardization and revision of the project. In August of the same year, the China Machinery Industry Federation issued a document to formally incorporate vibration and stress relief technology into the machine tool. Manufacturing standards, followed by the revision of vibration stress relief technology to casting, forging, welding basics and manufacturing manufacturing standards. In 2003, the National Association of Science and Technology selected the vibration aging as the conference paper. Not long ago, in early April 2008, the Commission of Science, Technology and Industry for National Defense issued the National Military Standard for Vibration and Aging - "Technical Requirements for Vibration Stress Relief of Armored Vehicles" (WJ2696-2008). All of this has greatly promoted the development and application of vibration stress relief technology.
VSR has grown from scratch in China. Now there are thousands of VSR equipment operating in China's machine tools, molds, forging, casting, woodworking, aviation, aerospace, metallurgy, mining, railway, shipbuilding, textile, nuclear power plants and other industries.
However, because of the traditional vibration and aging, there are still many problems, and it has not been included in the formal process flow by most enterprises. The heat aging treatment method is still widely used in the field of machinery manufacturing at home and abroad.
Fourth, the problems in the use of traditional vibration effects:
Although the vibration aging technology has obvious advantages in terms of efficiency, energy saving and environmental protection, the traditional vibration aging technology, that is, the sub-resonance technology, does have technical problems that have not been solved for decades, and cannot be incorporated into the formal process flow. It has also not been recognized by a wide range of companies and has been applied on a large scale.
1. Sub-resonance aging method: scanning from low speed to rated motor speed, looking for resonance peak, determining main and vibration frequency and sweep frequency range in sub-resonance area. The vibration treatment is performed for several tens of minutes at the sub-resonance frequency.
2. Problems with sub-resonance technology:
(1) There are strict requirements for support points, excitation points, pick-up points and directions, and it is necessary to continuously sweep and adjust the position. Therefore, the operation of the equipment must be operated by professionally trained personnel. It is difficult for the average worker to master the technology even if it is trained; the adjustment of the workpiece in the single piece production is quite cumbersome, and it is difficult to adjust the vibrator and the support point to the optimum state. A workpiece requires a process to be developed; artificially determining the need to process the formant, which requires a higher level of experience for the operator;
(2) Because the formant is searched by means of frequency sweep, and the motor speed is limited, when the workpiece resonance frequency exceeds the frequency range of the exciter, the workpiece resonance frequency cannot be found by scanning, and thus the workpiece cannot be effectively effective. Vibration treatment. National related data statistics sub-resonance technology can handle workpieces in the mechanical manufacturing coverage of only 23%.
(3) The effective vibration mode is less, the stress relief of vibration aging is unstable, and the elimination of stress cannot achieve the best result;
(4) The excessive noise is also the main reason why it is difficult to promote.
Fifth, the application of spectrum harmonic technology in the field of vibration aging:
Continued improvement in vibration aging technology. Researchers from all over the world have tried to improve the speed of the exciter in order to solve the frequency-finding problem of high-rigidity materials, and how to rationally formulate the vibration process plan of various workpieces as the main research and breakthrough direction. However, it seems to have entered a technical bottleneck. The improvement of motor speed is facing many technical problems. The continuous emergence of new materials and new equipment has also complicated the formulation of process plans. At the same time, when the vibration is not solved, the noise generated by the motor running at a high speed is required; the working current is high and the motor is heated. The vibration aging entered a slow development stage in the second half of the 20th century. However, with the rapid development of electronic equipment, the controller gradually evolved from simple manual control to single-chip microcomputer to computer control, using equipment control. The use of monitoring is more and more convenient and quick, but the key problems - low coverage, high noise, less vibration mode, poor stress relief, more manual intervention in the process plan, and complicated problems have not been substantially resolved. The application of vibration aging in enterprises has also entered a low tide period. The equipment originally purchased is either idle or can only be used as an experimental research topic in the laboratory. High-contamination, high-energy heat-aging furnaces continue to be used. It seems that the vibration aging is left to the enterprise only with shadows.
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