Rough benchmark selection principle? Refined benchmark selection principle?
Rough benchmark: 1. The principle of ensuring mutual position requirements;
2. The principle of ensuring the reasonable distribution of machining allowances for machined surfaces;
3. The principle of facilitating workpiece clamping;
4. The principle that rough benchmarks should not be reused in general;
Refined benchmark: 1. Principle of benchmark coincidence;
2. Unified benchmark principles;
3. The principle of mutual benchmarks;
4. Self-base principle;
5. The principle of easy clamping;