On flexible manufacturing in automobile production

Talking about flexible manufacturing in automobile production

1. Characteristics of flexible manufacturing

according to the standard classification of mechanical manufacturing science and the level of automation in the production system, flexible manufacturing can be divided into flexible manufacturing unit (FMC), flexible manufacturing system (FMS), flexible manufacturing line (FML) and flexible manufacturing factory (FMF). The biggest feature of flexible manufacturing is the flexibility of manufacturing. Its performance in automobile production is as follows

a. equipment flexibility: the equipment can complete a variety of processing, which is conducive to mass production, reduce inventory costs, improve equipment utilization and shorten processing cycle

b. flexible material transportation: material transportation equipment can transport a variety of materials, with high availability and utilization

c. flexible operation: the workpiece with the same processing technology can be processed in many ways, and it is easy to realize dynamic scheduling in case of machine failure

d. personnel flexibility: operators master a variety of skills and can work in small positions

e. path flexibility: workpiece processing can be completed through multiple paths of the manufacturing system, which is convenient to balance the load of the machine tool and enhance the stability and reliability of the system in the case of machine tool failure, tool wear, etc

f. process flexibility: the manufacturing process can produce a variety of products at the same time, with mixed ratio flexibility, and improve customer service level by providing diversified products

g. product flexibility: some parts can be added, removed or replaced at any time in the product, so as to improve the responsiveness to market product demand

h. batch flexibility: under a variety of production batches, the manufacturing system can obtain corresponding profits and maintain its profitability under various demand levels

i. expand flexibility: the manufacturing system is open and can expand its production capacity to meet the requirements of enterprises to expand new markets

j. production flexibility: without adding important manufacturing facilities, the manufacturing system can produce a variety of products and complete diversified production tasks

k. market flexibility: manufacturing system can survive and develop in the changeable market environment, and has strong comprehensive ability to adapt to the dynamic market environment

2. The role and development of flexible manufacturing in the automotive industry

the United States, Japan, the former Soviet Union, Germany and other developed countries successively carried out the research and development of flexible manufacturing technology and equipment from the late 1960s to the early 1970s. In 1976, Japan's farnaco company exhibited a flexible manufacturing unit composed of machining centers and labor robots, which provided an equipment foundation for the development of flexible manufacturing. In the 1980s, with the maturity of flexible manufacturing technology, flexible manufacturing has developed rapidly and is mainly used in aircraft and automobile manufacturing. Relying on the flexible automatic processing system composed of computers, machining centers and numerical control machine tools, the production mode of automobile is changed from single variety and large batch to small and medium batch, multi variety and lean production mode that meets the requirements of the market, and the economic benefits and management level of automobile production enterprises are greatly improved

in the foreign automobile industry, major automobile manufacturers such as general motors, Ford, BMW, Mercedes Benz, Toyota, Volkswagen, Renault, Volvo and other companies have adopted flexible manufacturing systems. For example, there are many kinds of pressure testing machines. An engine plant of Ford Motor Company in Canada realizes random mixed production of 4.6 L, 5.4 lv8 engines and 6.8 lv10 engines on the same automatic line (650000 sets per year); The driveline Department of General Motors began to make the same preparations in 1993 to adopt FMS to meet the manufacturing requirements of multiple varieties of transmission housing parts; According to the new development of Toyota's productivity mode published in 1983, the company's automobile output in three months was 364000, with a total of 4 basic models and 32100 models. The average output of each model was 17, with only 17 models producing the most and only 6 models producing the least. The Japanese automobile industry began to vigorously develop flexible manufacturing in the 1970s. By 1987, it had formed a large scale, with more than 20000 CNC machine tools and 21 flexible manufacturing production lines. According to the 8th statistical survey of specific machinery and equipment by the Ministry of foreign trade and industry of Japan, the transportation machinery manufacturing industry with automobile manufacturing as the core had 31 FMS in 1987 and increased to 818 in 1994. Especially for large automobile manufacturing enterprises, FMS is the most widely used, accounting for 41% of the total increase in seven years. Flexible manufacturing has created conditions for Japan's automotive industry to catch up with and surpass the United States in productivity. The small decline of Japanese cars in the international market is closely related to its flexible manufacturing

like developed countries, domestic automobile industry is also the birthplace of advanced manufacturing methods. In the 1980s, with the process of reform and opening up, China's auto industry began to make it difficult to recognize the yield point. The national auto industry systematically learned advanced production methods and manufacturing methods, including flexible manufacturing. In the middle and late 1980s, major manufacturers in the automotive industry began to try flexible manufacturing in some technological processes and product manufacturing, and initially accumulated experience. Since the end of last century, with the increase of the strength of domestic automobile enterprises, the large-scale entry of foreign companies and the improvement of production equipment, flexible manufacturing has developed rapidly in automobile industry. For example, the main automobile manufacturer FAW Group has begun to carry out flexible manufacturing in some production fields, using a variety of robots in welding workshops, and increasing manipulators and other automatic equipment in production processes, which can realize multi variety mixed line production to a certain extent; FAW Volkswagen Automobile Co., Ltd. uses the flexible automatic line of modular machine tool with CNC three coordinate module to produce car transmission and clutch housing. The beat of the automatic line reaches 40.5s, the annual production capacity is 360000 pieces, and the process capacity index cp>1.33, which can be produced without failure for 4 weeks; Another example is that Shanghai General Motors also has a flexible production line, which covers the manufacturing links of major assemblies and complete vehicles, and improves the speed of product replacement. With the development of auto industry, auto parts processing is also developing towards flexible manufacturing. FMS brings a high degree of flexibility in processing, making it possible to produce more kinds of parts while maintaining high productivity. As an important component module of auto parts production line, machining center provides a guarantee for reliable and efficient production in the field of auto parts production. The modularization of its open structure and flexible structure technology, as well as the further improvement of the cutting speed and accuracy of the machining center, have achieved better cost performance for the auto parts industry. In a word, flexible manufacturing doors are developing towards various fields of vehicle manufacturing

with the advent of various advanced processing technologies, flexible manufacturing technology itself is also constantly improving and improving. For example, a Swiss industrial income company has adopted a flexible manufacturing unit composed of a laser processing center, a CNC automatic lathe and an automatic grinder. Because the unit has changed to a laser processing center to replace the original milling machine, the productivity has been increased many times, and the products have high precision and good quality. Taking numerical control processing as an example, in order to provide basic equipment for flexible manufacturing, it is required that the numerical control system can only complete the usual processing functions, and should also have the functions of automatic measurement, automatic loading and unloading, automatic tool change, automatic replacement of main shaft head (sometimes with coordinate transformation), automatic error compensation, automatic diagnosis, incoming line and connection, especially according to the small requirements of users, the company can flexibly configure and integrate it. The continuous progress of various related technologies promotes the continuous expansion of flexible manufacturing scale, which will have a profound impact on automobile production

3. Conclusion

the traditional single variety and mass production mode of the automotive industry is transitioning to the production mode of multiple varieties, small and medium batches and "variant variables". The production mode dominated by producers is gradually changing to the production mode dominated by consumers. Flexible manufacturing is a better production mode to adapt to this change. On the basis of manufacturing technology, automation technology and information technology, flexible manufacturing in automobile production not only has the advantages of product flexible manufacturing, but also helps to combine the mutually independent processes of product design, manufacturing and operation management in the enterprise to form a complete and organic system with a large coverage in the enterprise, so as to achieve global dynamic optimization, overall high efficiency and high flexibility. Combined with the actual situation of enterprises, the development of flexible manufacturing technology will benefit automobile production enterprises and continuously improve their comprehensive strength

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