1. CNC machining workpieces have not been cleaned and there are no anti-oxidation measures. During the machining process, the parts will inevitably come into contact with coolant liquid, air, and water. Affected by these factors, white oxidation patches will appear on the surface of the workpiece. We use orthogonal The test analyzes the influence of three factors: coolant liquid, water and air on the production of white oxidized plaques. The levels are defined as presence and absence respectively. The coolant solution and water are dropped on the surface of the workpiece, and the air is isolated by applying Vaseline. The test lasts for 13 days (the machining cycle for the outer dimensions of the part is about 13 days). The results showed that surface oxidation corrosion occurred under the action of the coolant liquid and air, causing the parts to not meet the surface treatment requirements. Therefore, the failure to clean the workpiece and the lack of anti-oxidation measures are one of the reasons for the low qualification rate of parts manufacturing.

2. Lack of tooling equipment In order to verify the team's inference, we trial-produced and processed 3 other products with special polishing equipment during the test, and calculated the scrap rates respectively. After comparing the scrap rate of the test product with the scrap rate of this part, it was found that the scrap rate difference was nearly 8 times. Therefore, lack of polishing equipment is another reason for high product scrap rates.

The traditional polishing method is to install the workpiece on a rotating device and hold the sandpaper to press the outer circle of the part for polishing. The traditional polishing method has the advantages of simple operation and good economy, and is widely used in the mechanical processing industry. Its shortcomings are obvious, such as uneven polishing force, discontinuous feed, and low part polishing efficiency.

We look for tooling design ideas from traditional polishing methods and retain the advantages. The key points of polishing were extracted, including: polishing contact surface (hand-held sandpaper), polishing force (generated by arm pressure), and feed amount (palm movement). The mechanical structure was used to achieve the above points, and a set of universal polishing tooling was successfully designed. After using this tooling, the parts can be evenly stressed during polishing.

This tooling can be installed on the tool holder of the polishing equipment to achieve uniform feeding combined with the original functions of the equipment. At the same time, in order to prevent the polishing equipment from grinding the parts, polytetrafluoroethylene material, which is softer, stronger in toughness, and resistant to high temperatures, was selected as the material of the polishing head. For polishing sandpaper, we chose a certain type of polishing sandpaper with a soft texture and adhesive backing.

In actual use, the processing qualification rate of parts has been improved by optimizing the part polishing method. The design of universal polishing tooling is a highlight of this project. This tooling effectively solves the problems of traditional polishing methods such as inconsistent polishing force, discontinuous feed, and low polishing efficiency. It provides a basis and reference for future processing of other precision shaft parts. experience.

(edit：admin)