Grinding is the finishing process (such as cutting process) on the processed surface through the relative movement of the grinding tool and the workpiece under a certain pressure by using the abrasive particles coated or pressed on the grinding tool.
Grinding can be used to process various metal and non-metal materials. The processed surface shapes include plane, inner and outer cylindrical and conical surfaces, convex and concave spherical surfaces, threads, tooth surfaces and other profiles.
The processing accuracy can reach IT5~IT01, and the surface roughness can reach Ra0.63~0.01 microns.
Grinding methods can generally be divided into three categories: wet grinding, dry grinding and semi-dry grinding.

1. Wet grinding: also known as sand-coated grinding, the liquid abrasive is continuously injected or coated on the grinding surface, and the abrasive continuously slides and rolls between the work piece and the grinding tool to form a cutting motion. Wet grinding is generally used for coarse grinding, and the particle size of the micropowder abrasive used is coarser than W7.
2. Dry grinding: Also known as sand-embedded grinding, the abrasive is evenly pressed and embedded in the surface layer of the grinding tool. When grinding, only a small amount of auxiliary materials such as stearic acid mixed fat should be coated on the surface of the grinding tool. Dry grinding is often used for fine grinding, and the particle size of the micropowder abrasive used is finer than W7.
3. ③Semi-dry grinding: Similar to wet grinding, the abrasive used is paste grinding paste. Grinding can be done by hand or on a grinder. Before the workpiece is ground, other processing methods must be used to obtain higher pre-processing accuracy, and the remaining grinding allowance is generally 5 to 30 microns.