What matters most when sourcing surface finish for CNC parts?

The critical inputs are CAD revision, material grade, tolerance stack, surface finish, quantity, inspection scope and delivery target. Missing any one of these usually creates quote revisions later.

Can FabVector quote from a STEP or STL file?

Yes. STEP and STL can start the structured RFQ. Drawings, GD&T, material certificates and inspection requirements should be attached when the part has regulated or tolerance-critical features.

What process route is usually reviewed first?

Select finish after material and function are clear, not as a cosmetic afterthought.

What documentation can be requested?

CMM inspection, FAI, CoC, material certificates, traceability records and packing photos can be requested when the project requires them.

guidesurface finish for CNC parts

Surface Finish Selection for CNC Parts: Anodizing, Plating, Passivation and Polishing

How to choose surface finishes for CNC machined parts and understand tolerance impact before requesting a quote.

2026-06-30 · FabVector Engineering

Passivated stainless finish — Passivation

What buyers are trying to solve

Searches for surface finish for CNC parts usually come from engineering or procurement teams that already have a CAD model and need a manufacturable route, not a generic machining definition. The decision is normally about material risk, tolerance risk, surface finish, inspection paperwork and whether a supplier can move from prototype to repeat production without changing the process.

Best-fit applications

Buyers comparing corrosion resistance, wear resistance, cosmetics and dimensional effects.
Aluminum, stainless steel, copper and steel parts with functional finish requirements.
RFQs where finish choice can change tolerance, masking and inspection cost.

Manufacturing route

Select finish after material and function are clear, not as a cosmetic afterthought.
Define which surfaces need masking, coating allowance or post-finish inspection.
Separate cosmetic acceptance from functional dimensions.

Material and finish choices

Aluminum: Type II anodizing for color/corrosion, Type III hardcoat for wear.
Stainless: passivation or electropolishing for corrosion and cleanability.
Copper and brass: nickel, tin or controlled polishing depending on conductivity and corrosion needs.

Risk controls before quoting

Coatings can add thickness, remove material or round edges.
Threads, bores and sealing faces often need masking or allowance.
Color matching is different from engineering performance and should be specified separately.

RFQ inputs that improve quote accuracy

Material, finish standard, color, thickness and masked features.
Which dimensions are measured after finish.
Environmental exposure: salt spray, coolant, cleaning chemicals or outdoor use.

Related FabVector resources

When the part includes thin walls, sealing faces, tight datums, threaded features or inspection requirements, upload the CAD model through the structured RFQ flow so material, finish, tolerance, inspection and delivery expectations stay attached to the same request.

Related resources

All CNC finishes Material × finish matrix Anodizing Type II

RFQ next step

Turn this requirement into a quote package.

Upload CAD, select material, finish, tolerance, inspection and delivery context. FabVector keeps the quote inputs tied to the same engineering request.

Start structured RFQ