Article Surface finish

Surface finish for CNC parts: what to agree at enquiry stage

Surface finish can affect cost, lead time, functional faces, and later assembly. If Groundmetal should arrange it, include it in the enquiry.

Surface finish is often discussed at the end, but for precise parts it can affect production from the first drawing. If Groundmetal should arrange a surface finish, include it in the enquiry with the drawing, material, and quantity.

Mark functional faces, fits, threads, precise holes, and areas that must remain protected or dimensionally accurate. A finish layer can affect assembly, bearing seats, gear function, or later use of the part.

What should be agreed before production?

Topic Why it matters
Finish type Affects lead time, cost, and handling.
Functional faces Some faces must remain accurate or protected.
Threads and holes They may need protection or cleaning.
Gearing and fits Clarify whether they are finished or protected.
Packaging The finished surface must be protected during handling and delivery.

Checklist

  • State the required finish type.
  • Mark functional faces, threads, fits, and precise holes.
  • State whether Groundmetal should arrange the finish.
  • Add packaging and delivery requirements.
  • When unsure, describe where the part will operate.