Replace the old process I with compound machining

2022-08-24
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Engine crankshaft: composite processing replaces the old process (I)

after entering the 21st century, great changes have taken place in the manufacturing process and cutting tools of engine crankshaft. The multi tool turning process and manual grinding process, which have led for more than half a century, are gradually withdrawing from the historical stage due to low machining accuracy and poor flexibility. High speed and high efficiency composite machining technology and equipment have rapidly entered the automobile and parts manufacturing industry. High speed and high efficiency composite machining technology has been applied to a considerable extent in crankshaft processing and production, and will be its inevitable development trend

current situation of crankshaft processing technology and equipment

at present, most of the older crankshaft production lines in China are composed of ordinary machine tools and special machine tools, with relatively low production efficiency and automation. Rough machining equipment generally adopts multi tool lathe to turn crankshaft main journal and connecting rod journal. The process quality is unstable, which is easy to produce large machining stress, and it is difficult to achieve a reasonable machining allowance. Mq8260 and other ordinary crankshaft grinding machines are widely used for rough grinding, semi fine grinding, fine grinding and polishing, which are usually operated manually, with unstable processing quality and poor dimensional consistency

one of the main characteristics of the old production line is that there are too many ordinary equipment. According to the processing of nodular cast iron crankshafts, there are 35 ~ 40 equipment in a production line. The author once examined a domestic forged steel crankshaft production line. The rough machining adopts ordinary external milling to process the main journal and connecting rod journal, and then the NC fine turning of the main journal and connecting rod journal, and then the grinding of multiple processes can be transferred to the finishing process. Therefore, this production line has more than 60 equipment, resulting in a long product turnover line and a large site occupation area. Its production efficiency is completely improved by the decomposition process and margin of multiple equipment

today's automobile engine crankshaft manufacturing industry is facing the following problems:

1 Multi variety and small batch production

2. The delivery time is greatly shortened

3. Reduce production costs

4. The emergence of difficult to cut materials has significantly increased the difficulty of machining. In machining, many problems that need to be solved to realize super fitting, such as hard cutting

5. In order to protect the environment, it is required to use less or no cutting fluid, that is, to realize pre stripping cutting or quasi dry cutting between the sample and the experimental plate after drying

based on the above situation, since the beginning of the 21st century, high-speed, high-precision and efficient composite processing technology and equipment have been rapidly applied in the industry of adjusting the left and right level of the body by leaning on the side of the swing rod through the "policy guidance + market-oriented environment", and the production efficiency has been greatly improved, so the number of production equipment in the engine crankshaft production line has been reduced. The author once saw in a car engine crankshaft production line that there are only about 13 equipment in the whole line (including heat treatment and surface strengthening), with short product turnover line, high processing efficiency and easy quality control and management

development of crankshaft compound machining technology

in the late 1980s, Boehringer company and Heller company in Germany developed a perfect crankshaft turning turning and drawing machine tool. This machining process is the perfect combination of crankshaft turning process and crankshaft turning and drawing process. It has high production efficiency, good machining precision, strong flexibility, high degree of automation and short tool change time. It is especially suitable for the machining of crankshaft with countersunk grooves. After machining, the crankshaft can be polished directly, Rough grinding process is omitted. Therefore, crankshaft turning and drawing processing technology is one of the popular processing technologies in crankshaft rough machining in the world at present

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