How to improve the surface finish of CNC machining?
1.1 The workpiece is not cleaned and there is no anti-oxidation measures. During machining, parts inevitably come into contact with coolant, air and water. Affected by these factors, white oxide spots appear on the surface of the workpiece. We used orthogonal experiments to analyze the influence of three factors of cooling fluid, water and air on the white oxide spots, which were defined as presence and absence, respectively. Put the original coolant and water droplets on the surface of the workpiece, apply Vaseline to isolate the air. The test time is 13 days (the processing cycle of the part dimensions is about 13 days). The results show that under the action of the original coolant and air, the surface is oxidized and corroded, resulting in the parts not meeting the surface treatment requirements. Therefore, uncleaned workpieces and no anti-oxidation measures are one of the reasons for the low yield of parts.
1.2 Insufficient tooling equipment In order to verify the team's inference, we used special polishing equipment to trial-manufacture and process another 3 products during the test, and calculated the rejection rate respectively. Comparing the scrap rate of the test product with the scrap rate of the part, it is found that the scrap rate differs by nearly 8 times. Therefore, the lack of polishing equipment is another reason for the high product rejection rate.
2 Improvement measures
The traditional polishing method is to install the workpiece on a rotating equipment and press the outer circle of the part with sandpaper for polishing. The traditional polishing method has the advantages of simple operation and good economy. Widely used in machining industry. Its shortcomings are also obvious, such as: the polishing force is not constant, the feed is discontinuous, and the polishing efficiency of parts is low. We look for tooling design ideas from traditional polishing methods and retain the edge. The polishing points are refined, including: polishing contact surface (hand-held sandpaper), polishing force (generated by arm pressing), feed speed (palm movement), using mechanical structure to achieve the above points, and successfully designed a set of general polishing tool. After using this tool, the parts are polished evenly with force. The tooling can be installed on the tool holder of the polishing equipment, and combined with the original functions of the equipment, it can achieve uniform feeding. At the same time, in order to avoid the polishing equipment grinding parts, the material of the polishing head is made of softer, tougher, and high temperature resistant PTFE material. For polishing sandpaper, we opted for some type of polishing sandpaper, which is softer and adhesive-backed. The polishing head material is made of high temperature resistant polytetrafluoroethylene. For polishing sandpaper, we opted for some type of polishing sandpaper, which is softer and adhesive-backed. The polishing head material is made of high temperature resistant polytetrafluoroethylene. For polishing sandpaper, we opted for some type of polishing sandpaper, which is softer and adhesive-backed.
3 Conclusion
By optimizing the polishing method of the parts, the processing qualification rate of the parts is improved. The design of the universal polishing tool is a highlight of this project. The tool effectively solves the problems of inconstant polishing force, discontinuous feeding and low polishing efficiency in traditional polishing methods. Provide basis and reference for processing other precision shaft parts in the future. experience.