What is the main use of sandpaper？

The main function of sandpaper is to polish, polish and trim the surface of different materials. Specifically, sandpaper can achieve the following functions:
1. Smooth surface: Sandpaper can help remove uneven areas and make the surface smoother. Especially in woodworking and paint finish, sandpaper is often the last step to remove rough surfaces and ensure a smooth finish.
2. Remove old coating: If a new paint or coating needs to be applied, sandpaper can help remove the old coating in order to create a new adhesive layer on the surface of the object.
3. Corner dressing: Whether it is woodworking or metal working, corner dressing is often needed to meet specific design requirements. Sandpaper can precisely sand and trim the corners so that they are smooth and in line with the requirements.
4. Grinding materials with different hardness: the particle thickness of sandpaper is different, which can be used for grinding and dressing materials with different hardness. For materials with different hardness such as wood, glass and metal, sandpaper of different particle thickness can be selected.