The remaining roughness of the mechanical drawing is 3.2 6.3, and I can't hit 3.2 for the parts now, but I want to control it. Can I write the remaining roughness of 3.5?

1. The roughness mark value is a series, and ... 3.2, 6.3 ... is the first series, which is recommended.

2. If necessary, consider choosing the second sequence, ... 2.5, 5.0, 10. Not recommended, it has been cancelled in the current national standard.

3. Your processing technology can reach 3.5um, but it can't reach 3.2um. Are you sure?

4. The requirement of surface roughness is mainly to meet the demand, not the machining ability.

5. it should not be a problem for most equipment to process the surface of Ra3.2 with the current technology.

6. If it is Rz3.2, it may be a bit difficult.

7. Recommended practice: Ra6.3 can meet the requirements in use, so the design department will mark Ra6.3 on the drawings.

8. If 3.2um must be marked as required, the unqualified products shall be approved by the design department and degraded for use.

9. If you want to mark Ra3.5 on the map, you must be careful and never let it become a joke.