The following three points should be paid attention to when determining the positioning datum and clamping scheme:
(1) Strive to unify the benchmarks of design, process, and programming calculations.
(2) Minimize the number of clamping times, and try to process all the surfaces to be processed after one positioning.
3) Avoid using the machine-occupied manual adjustment scheme.
(4) The fixture should be open, and its positioning and clamping mechanism cannot affect the tool movement during processing (such as collision). When encountering such a situation, it can be clamped by using a vise or adding a bottom plate to draw screws.