In what polishing scenarios are coarse abrasives and fine abrasives respectively used?

Application scenarios of coarse abrasives

High initial surface roughness:
When there are big scratches, pits or unevenness on the surface of the workpiece, coarse abrasives can get rid of these defects quickly and lay a good foundation for the following polishing steps.

Large material removal:
When a lot of material needs to be removed fast, like in the initial processing of castings and forgings, coarse abrasives are the first choice because of their larger particle size and stronger cutting ability.

Low surface finish requirements:
In some application situations, such as the initial processing or pre-treatment of some mechanical parts, when the requirements for surface finish aren't high, using coarse abrasives can cut costs and improve processing efficiency.

Processing of specific materials:
For some hard and brittle materials, like ceramics and glass, coarse abrasives can effectively avoid material cracking or chipping during the initial processing stage.

Application scenarios of fine abrasives

Fine polishing:
In cases where a high surface finish is needed, like for optical components and parts of precision instruments, fine abrasives can remove the tiny scratches left by coarse abrasives and make the surface like a mirror.

Final surface treatment:
At the final stage of processing the workpiece, using fine abrasives for polishing can make sure the surface quality meets the design requirements and improve the overall performance and appearance of the product.

Less material damage:
Fine abrasives have smaller particle sizes and relatively weaker cutting power, so they cause less damage to the material during the polishing process and are suitable for processing materials that are easy to deform or get damaged.

Improved wear resistance and corrosion resistance:
The surface polished by fine abrasives is smoother. It can reduce the contact area between friction and corrosive substances and the material surface, thereby improving the wear resistance and corrosion resistance of the workpiece.