Machining is usually divided into: rough machining, semi - finishing, finishing. Obviously, precision machining, high precision grinding belongs to the finish machining. High precision grinding: usually called fine grinding. Precision machining is subordinate to high precision grinding. A fining process in which a fine-grained grinding strip is pressed on a rotating workpiece at a certain pressure and subjected to reciprocating oscillations in the axial direction for micro cutting.

Super-finishing is generally arranged after the fine grinding process, the processing allowance is very small (generally 5 ~ 8 micron), often used for processing a variety of internal and external cylindrical surface, cone surface, plane, sphere, such as crankshaft, roll, rolling bearing ring and a variety of precision parts. The surface roughness of the workpiece can reach R0 after super-finishing. 08 ~ 0. 01 micron, the surface processing lines are formed by the cross of corrugated curves, so it is easy to form oil film, improve the lubrication effect, so the wear resistance is good.

Due to the low temperature in the cutting zone, the surface layer has mild plastic deformation, so the surface has low residual compressive stress. The grain size of the grinding strip commonly used in super-finishing is generally W0. 5 ~ W28; The commonly used cutting fluid is about 80% kerosene and about 20% oil, and through strict filtration; The pressure of the grinding strip is generally 0. 05 ~ 0. 3 million mpa; The grinding strip amplitude is generally 1 ~ 6 mm; The circumferential speed of the workpiece generally does not exceed 700 m/min.

If you need to improve the shape accuracy of the parts and remove the grinding metamorphic layer, the allowance of 0 must be removed. At this time, super-finishing is divided into coarse and fine stages. Coarse processing is used with coarser grain size grinding bar, larger speed and grinding bar pressure, and a smaller value is taken for finishing.