In the machining of metal parts, according to the different structure and technical requirements of the hole, different processing methods can be used.

 These methods can be summarized into two categories: one is to perform hole processing on a solid workpiece, that is, to process a solid workpiece. Hole; the other type is semi-finishing and finishing of existing holes

Non-matching holes are generally drilled directly on the solid workpiece by drilling; for matching holes, it needs to be drilled on the tomb, according to the accuracy and surface quality requirements of the processed hole, using reaming, boring, Grinding and other finishing methods for further processing.

Reaming and boring are typical cutting methods for finishing existing holes. To realize the precision machining of holes, the main machining method is grinding. When the surface quality of the hole is very high, it is necessary to use fine boring, grinding, honing, rolling and other surface finishing methods; the processing of non-circular holes requires the use of slotting, broaching and special processing methods.

The inner hole surface is also one of the main surfaces on the part. According to the different functions of the part in the mechanical product, the inner hole of different structure has different precision and surface quality requirements. According to the relative connection relationship between holes and other parts, they can be divided into matching holes and non-matching holes; according to their geometric characteristics, they can be divided into through holes, blind holes, stepped holes, tapered holes, etc.; according to their different geometric shapes, It can be divided into round holes and non-round holes.