Domestic development of the grooving knife for the

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Localized development of slotting knife for nozzle needle valve body

the oil pump branch of YITUO Group has introduced two 12 position machine tools (dr-12) made in Switzerland for processing nozzle needle valve body (zck150j). There are three kinds of grooving knives that are necessary for the machine tool to process the needle valve body. Because the randomly imported knives are worn and scrapped after using for a period of time, the machine tool is in a shutdown state. Because the manufacturing and grinding of the slotting knife are quite difficult, there is no domestic supply, and purchasing from abroad is not only expensive, but also the supply cycle cannot be guaranteed. Therefore, the realization of the domestic coherent data display of the tool has become an important technical topic of our factory, for which a special research group has been established

1 analysis of technical requirements

the needle valve body slotting cutter (see Figure) is a small cavity processing tool with complex geometry (mostly spatial angle). There are high requirements for machining accuracy and surface roughness of cutting tools. Because there is no drawing of the tool, only physical surveying and mapping can be taken, but it is difficult to ensure the surveying and mapping accuracy. In addition, our factory has no micro parts processing equipment, so it is difficult to process with ordinary machine tools. In view of this, the basic development objectives determined by the research group are: ① the cutting tools basically meet the use requirements and can be processed into qualified products; ② The durability of the tool reaches 50% of the imported tool (about 500 workpieces can be processed)

figure sketch of needle valve slotting cutter

2 cutter material and processing technology

according to the surveying and mapping results and technical analysis of imported slotting cutters, with the increase of per capita income of domestic residents and the improvement of consumption level, W18Cr4V and w12cr4v3mo3coo are selected as cutter materials. According to the technical requirements for cutter processing accuracy and surface roughness, combined with the existing processing equipment and production batch of our factory, After many technical demonstrations and process tests, The process flow of manufacturing the slotting cutter is determined as follows: rough turning the outer circle (f6mm, with a grinding allowance of 0.8 ~ 1mm) → rough grinding the outer circle → grinding the two end faces → grinding the two locating surfaces of the handle → turning the eccentric circle of the blade → turning the eccentric circle of the neck 30 → milling the front knife surface of the blade (1mm higher than the center) → heat treatment (quenching hardness 63-66hrc) → grinding the outer circle of the handle (f6mm) → grind the two locating surfaces of the handle part, grind the eccentric circle of the blade part → grind the 3 ° eccentric circle of the neck part → grind the front knife surface → grind the forming of the blade part and the 6 ° main rear angle, grind the right 10 ° eccentric circle → grind the left 10 ° eccentric circle → grind the 11 ° eccentric circle of the head part → grind all 20 ° rear angles → grind the rear angle of the knife tip r 20 ° → electric lettering

3 design and manufacture of secondary tools

according to the process requirements of tool manufacturing, the following secondary tools are specially designed and manufactured: ① eccentric circular fixture for vehicle; ② Eccentric round fixture of car neck; ③ There are 17 kinds of jigs, such as the jig for milling the cutting surface

4 tool use effect

through more than a year of technical research and trial production, that is, on the basis of equipped with different fixtures, after three batches of feeding, more than 10 cutting tests, small batch trials and many technical improvements, the domestic slotting cutter has finally been successfully developed. Compared with imported cutters, the use effect of domestic cutters is quite satisfactory. For example, each imported slotting cutter can generally process 1000 workpieces, and the best one can process 2000 workpieces; However, each homemade slotting cutter can process 800 pieces, and the best one can process 1400 pieces, with the durability reaching 70% - 80% of that of imported cutters, while the price of homemade cutters is only 1/8 of that of imported cutters, which can significantly reduce the processing cost and save a lot of foreign exchange for enterprises. At present, the oil pump branch has used all the self-made grooving knives of our factory instead of imported knives, and achieved high technical and economic benefits

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