Zhangjiagang Weibo Machinery followed the news of the previous issue. The surface after EDM is more difficult to grind than the surface after ordinary machining or heat treatment, so precision EDM should be used before the end of EDM, otherwise a hardened thin layer will be formed on the surface. If the EDM finishing specification is not properly selected, the depth of the heat-affected layer can reach 0.4mm. The hardened thin layer is harder than the matrix and must be removed. Therefore, it is recommended to add a fine grinding process to the pipe bender to completely remove the damaged surface layer and loosen it into an average rough metal surface, which provides a good foundation for polishing.

In order to obtain better polishing quality so that the coating and spraying process can exert a greater anti-rust and anti-corrosion effect, it is important to have high-quality polishing tools and accessories such as whetstone, sandpaper and abrasive materials.

1. After the raw materials of the parts of the explosion-proof pipe cutting machine have been processed by rough turning, after being processed by fine turning, milling, EDM, rough grinding, etc., the surface has fine lines or car marks that are discernible to the naked eye. Grinding and removal of car marks and EDM marks was carried out using a rough grinding lathe at 350,000 rpm during machining.

2. Then replace the oilstone wheel and grind the parts. If it is impossible to use a grinding machine for processing, it will be better to carry out manual whetstone grinding, and the effect of adding kerosene as a lubricant or coolant will be better. The selection of the whetstone should start from the small size. If there is a large cutting mark, it should be removed by lathe machining.

3. Simple polishing with sandpaper is to start from small-mesh sandpaper to large-mesh sandpaper according to the number of meshes. Generally speaking, if the metal surface is already very flat, you can start grinding from 600, if it is not very flat, you can start from 400 or 200. Mesh number refers to how many particles there are per 1 inch, the larger the particles, the finer the particles.

4. Sandpaper can be divided into dry sandpaper and wet sandpaper (commonly known as water sandpaper). The automatic pipe cutting machine usually exceeds 1200 if it is wet sandpaper and needs to be matched with abrasives. There are two types between 600 and 1000, and almost all of them are below 600. dry sandpaper. For water sandpaper and water grinding, appropriate grinding paste should be added. Generally speaking, manual grinding is enough to grind to about 1000. If it is finer, it will cause difficulties in painting and coating, and the cost will increase significantly.

5. When using different types of sandpaper, the polishing direction should be changed by 45 degrees or 90 degrees, so that the stripe shadows left by the previous type of sandpaper after polishing can be easily distinguished. In order to avoid scratches and burns on the parts of the explosion-proof pipe cutting machine, when grinding with 200 and 500 sandpaper, the grinding machine speed should be carefully changed according to the production process, and the 45-90 degree change should be carried out in two different directions during polishing.