The purpose of function compounding is to further improve the production efficiency of the machine tool and minimize the time used for non machining assistance. Through the combination of functions, the use scope of the machine tool can be expanded, the efficiency can be improved, and one machine can be used for multiple purposes and one machine can have multiple functions. That is, a CNC lathe can realize both turning and milling functions; Or in the milling machine tool can also achieve grinding.

The common lathe has a wide range of machining objects, a wide range of spindle speed and feed adjustment, and can process the internal and external surfaces, end faces, and internal and external threads of workpieces. This kind of lathe is mainly manually operated by workers, with low production efficiency, and is suitable for single piece, small batch production and repair workshops.