1. As a precision benchmark, the surface should be processed at the beginning of the CNC machine tool processing sequence, because it should be used to locate other surfaces in subsequent processes.That is, "benchmark before others".
2. When machining the precision datum, coarse datum shall be used for positioning.In single piece, small batch production, or even batch production, for the shape of complex or large size of castings and forgings, as well as large size error of the blank, CNC machine tool machining process should be arranged before the first line process, in order to provide accurate benchmark processing.
3. After the precision benchmark is processed, roughing, semi-finishing and finishing should be carried out on the main surfaces with higher precision requirements.The surface with high precision also needs finishing.
4. Before the important surface processing, the precision benchmark should be recuperated to ensure the machining accuracy of the important surface.
5. For processes that are prone to waste products, CNC machine tool finishing and finishing can be placed in the front, and some minor surface processing can be placed in the back.