Buyer guide
CNC Surface Finishes: Selection Guide for Machined Parts
A finish is part of the part specification. Select it with the base material, dimensions, environment and acceptance evidence in view.
Start with the function
- Separate corrosion protection, wear, appearance, conductivity and cleanability goals
- State the surface or roughness requirement on the drawing where it matters
- Identify masking, contact, sealing and mating surfaces
- Check whether the treatment changes dimensions or edge definition
Common finish decisions
- Anodizing is commonly considered for aluminium appearance and protection
- Passivation and electropolishing are common stainless-steel choices with different surface goals
- Plating, polishing, bead blasting and painting serve different functional and cosmetic needs
- Ask for colour, thickness, coverage and test or certificate requirements
Approve the result
- Use a representative sample when colour or appearance matters
- Inspect critical dimensions after finishing, not only before it
- Record the finish specification and approved reference with the order
- Confirm rework limits before production begins