Surface Finishes
Surface finishes for appearance, protection, and function.
Compare common finishing options for CNC machined, printed, cast, and molded parts — from as-machined to anodizing, powder coating, polishing, and plating.
Match Finish To Function
Choose finish by cosmetic, environmental, and tolerance needs.
Appearance, corrosion resistance, wear, electrical insulation, and dimensional impact all shape the right finish for a part.
Finishing capability and availability vary by process and material. Confirm required finish, color standard, and critical dimensions in the RFQ before production.
Common Finishes
Practical starting points for finish selection.
As-Machined
Materials: all machinable metals and plastics. Purpose: fastest turnaround for non-cosmetic parts. Appearance: visible tool marks and natural material finish. Dimensional impact: none beyond machining tolerances. Masking: not applicable. Color: natural material tone. Limits: not suitable for corrosion-prone environments without a protective coating.
Bead Blasting
Materials: aluminum, steel, stainless steel, and some plastics. Purpose: uniform matte surface that hides minor tool marks and prepares parts for coating or anodizing. Appearance: even satin texture. Dimensional impact: removes surface texture only — verify critical features after blasting. Masking: protect threads and precision bores. Color: lightens natural metal tones. Limits: roughness varies with media and pressure; confirm expectations in the RFQ.
Anodizing
Materials: aluminum (some titanium). Purpose: corrosion protection, wear resistance, and color. Appearance: matte to satin; clear, black, or dyed colors. Dimensional impact: thin oxide layer grows from the surface — account for critical fits and threads. Masking: threads and close-tolerance bores need masking. Color: confirm color standard (RAL, Pantone, or sample). Limits: process and color results depend on the alloy; not available on steel or plastics.
Powder Coating
Materials: steel, stainless steel, aluminum, and castings. Purpose: durable protective and decorative layer. Appearance: smooth or textured; broad color range. Dimensional impact: thicker film than paint — critical on threaded holes and mating fits. Masking: required for mating surfaces and threads. Color: RAL, Pantone, or custom sample. Limits: adds lead time; tight internal features need masking and may be impractical.
Polishing & Brushing
Materials: stainless steel, aluminum, brass, and copper. Purpose: smooth reflective or directional satin appearance. Appearance: mirror polish or fine brushed lines. Dimensional impact: removes small amounts of material; edges may soften slightly. Masking: not typical. Color: natural metal tones. Limits: large polished areas add cost; specify polished zones on the drawing.
Electroplating (Ni / Zn / Cr)
Materials: steel, brass, and copper. Purpose: corrosion and abrasion resistance, or a decorative metallic layer. Appearance: bright or matte metallic tones. Dimensional impact: thin layer — still account for threads and press fits. Masking: selective plating or masking needed. Color: silver, zinc tones, or chrome. Limits: confirm base material, environment, and applicable compliance requirements in the RFQ.
Finish Comparison
Shortlist finishes before requesting a quote.
| Finish | Main effect | Typical use |
|---|---|---|
| As-Machined | Fastest turnaround; light tool marks may show | Prototypes, internal, non-cosmetic parts |
| Bead Blast | Uniform matte, hides tool marks | Housings, enclosures, prep for coating |
| Anodizing Type II | Corrosion resistance, color options | Aluminum housings, cosmetic aluminum parts |
| Anodizing Type III | Hard, wear-resistant oxide layer | Wear surfaces, sliding and threaded parts |
| Powder Coating | Thick, durable, multi-color | Structural frames, outdoor enclosures |
| Electroplating (Ni/Zn/Cr) | Thin metallic layer, corrosion/abrasion resistance | Fasteners, contacts, decorative metal |
Tolerance Interaction
Finish and tolerance must be reviewed together.
Coatings and treatments change final dimensions. Call out critical surfaces and masking early to avoid rework.
- Mark cosmetic vs functional surfaces on drawings
- Specify color standard (RAL / Pantone) where needed
- Define masking zones for threads and tight tolerances
- Request finish samples for visual approval
Finish Review
Send finish callouts with your drawings.
Share CAD, material, quantity, and the required finish so the team can confirm feasibility, masking, and lead time.