Usually several surfaces must be machined on a CNC machining part. This kind of surface not only has certain precision regulations, but also has certain position regulations between the surfaces. In order to achieve this precision, the processing order of each surface of the CNC machined parts cannot be randomly assigned, but must comply with certain standards. This is the selection and transformation of precise positioning benchmarks that determine the processing order, and preprocess is the post-process. Prepare the standard for precise positioning of the reference.

machining a fine datum surface

The necessity of CNC machining sequence

1. Before processing the key surface, a trimming should be carried out on the fine datum to help ensure the processing accuracy of the key surface.
2. After finishing the reference processing, the key surfaces with high precision requirements are solved to carry out rough machining, semi-finishing and finishing. Donegal CNC precision parts must be finished with very high machining accuracy.

machining a fine datum surface
3. The surface used as a precision reference should be processed at the beginning of the entire CNC machining process, because it is used for precise positioning when processing other surfaces in the subsequent process. That is, “benchmark first, then others”.
4. When machining a fine datum surface, a rough datum must be used for precise positioning. In loose parts, small batch manufacturing, and even mass production, for castings and steel castings with complex shapes or large specifications, and rough specifications with large deviations, they should be allocated first before the machining process of mechanical equipment The line drawing process is convenient to show the alignment datum for fine datum processing.

machining a fine datum surface
5. For processes that are very prone to waste, finishing and smoothing can be appropriately placed in front, and some major and minor surface processing can be placed later.


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