Surface finishing for custom parts

Choose the finish around function—not color alone.

Compare anodizing, micro-arc oxidation, painting, powder coating, plating and other finishing routes by material, corrosion, wear, appearance, conductivity and dimensional impact.

Send Drawings for Review Compare Anodizing Options

Material and alloy reviewed
Masking and coating allowance checked
Color, gloss and texture defined
Final route confirmed per project

Type IIClear anodized

Type IIIHard anodized

ElectrolyticBronze tone

Powder coatRAL color

PlatingNickel finish

MAO / PEOCeramic oxide

Start with the drawingCall out the specification, thickness and finished dimensions.

Define protected areasThreads, bores, seals, grounds and contact marks may need masking.

Control appearanceUse a color standard, gloss range, texture and approved sample when needed.

Confirm the service routeAvailability and inspection are agreed before production release.

Finishing options

A practical surface-treatment range.

These are common project-review options, not a one-size-fits-all catalog. Final availability depends on material, geometry, quantity, specification and approved processing route.

Machined & mechanical finishes

Control texture, burrs and appearance before a coating is applied—or use the prepared surface as the final finish.

As machinedVisible tool marks; economical when no additional coating is required.
Deburring & tumblingRemoves loose burrs and softens edges on suitable small parts.
Bead or sand blastingCreates a more uniform matte texture and prepares many parts for coating.
BrushingProduces a controlled directional grain on exposed metal surfaces.
PolishingReduces surface roughness and can create satin or reflective appearances.

Oxide & conversion finishes

Grow or convert the surface to improve corrosion behavior, wear performance, paint adhesion or appearance.

Type II anodizingConventional sulfuric-acid anodizing for aluminum, often selected for corrosion protection and color.
Type III hard anodizingA thicker, harder anodic coating for aluminum parts where wear resistance is more important.
Dyed anodizingColor dye is absorbed into the porous anodic layer before sealing.
Electrolytic coloringMetal salts are deposited in anodic pores to create durable bronze-to-black tones.
Micro-arc oxidation (MAO / PEO)High-voltage micro-discharges form a ceramic-like oxide on aluminum, magnesium or titanium.
Chemical conversion coatingA thin conversion layer for aluminum corrosion protection, conductivity needs or paint preparation.
Black oxide & phosphatingConversion treatments commonly reviewed for ferrous parts and subsequent oil, wax or paint systems.

Applied coatings & plating

Add a separate coating layer when the project needs color, environmental protection, conductivity or a specific surface property.

Liquid painting / spray paintingFlexible color, gloss and coating-system selection for metal and selected plastic parts.
Powder coatingElectrostatically applied powder is cured into a durable coating for many metal parts.
E-coating / electrophoresisCharged coating particles provide uniform coverage, including on complex conductive components.
ElectroplatingZinc, nickel, chrome, copper, tin, silver or gold can be reviewed according to protection, wear, conductivity and appearance.
Electroless nickel platingAutocatalytic nickel-phosphorus deposition supports more uniform coverage on complex geometry.
PVD coatingA thin vapor-deposited coating can be considered for wear, friction or decorative requirements.

Stainless steel & plastic options

Some materials need a chemistry- or tooling-specific route rather than a conventional applied coating.

PassivationRemoves free iron and contaminants from stainless steel to support its passive corrosion-resistant surface.
ElectropolishingElectrochemically removes a controlled surface layer to smooth and brighten suitable metals.
Plastic paintingAdds color or functional coating when the resin, preparation and adhesion system are compatible.
SPI mold textureDefines molded plastic gloss and texture at the tool surface rather than as a post-machining coating.
Laser markingAdds durable identification, traceability or graphics without a separate label.

Anodizing comparison

Type II, Type III, coloring and MAO are not interchangeable.

Use the functional requirement and drawing controls to select the route. “Type II” and “Type III” are anodic-coating classifications—not two-electrode and three-electrode processes.

Finish	How it is formed	Best starting point for	Typical appearance	What to define on the drawing
Type II anodizing	Conventional sulfuric-acid anodic oxide	Corrosion protection, appearance and dyeing	Clear, black or dyed colors; matte or gloss depends on pretreatment	Specify alloy, thickness, color, sealing, masking and contact-mark location
Type III hard anodizing	Hard anodic oxide, normally thicker than Type II	Wear, surface hardness and stronger functional protection	Usually clear, gray, dark bronze or black; often more matte	Allow for dimensional change and mask precision bores, threads, sealing and electrical contact areas
Dyed anodizing	Dye absorbed into anodic pores before sealing	Broader cosmetic color selection	Color depends on alloy, pretreatment, coating and lot	Provide a physical sample or color target plus acceptable lot-to-lot variation
Electrolytic coloring	Secondary electrolytic deposition of metal salts in anodic pores	Weather-resistant architectural or industrial color	Commonly bronze, gray and black rather than a full bright-color spectrum	Define target tone, gloss, alloy and acceptable color range
Micro-arc oxidation / PEO	Plasma-assisted high-voltage oxidation producing a ceramic-like layer	High wear, thermal or electrical-insulation requirements on light alloys	Typically gray, white or process-dependent; rougher and more functional	Confirm substrate, target properties, thickness, roughness, sealing and post-machining needs

Choose by project goal

Match the finish to the failure mode.

“Best finish” only has meaning after the substrate, environment, mating features and acceptance criteria are known.

Corrosion protection

Anodizing, conversion coating, passivation, zinc or nickel systems, painting and powder coating may be considered.

Wear & surface hardness

Type III hard anodizing, MAO/PEO, electroless nickel or selected PVD coatings may be a better starting point.

Cosmetic color

Dyed anodizing, electrolytic coloring, liquid paint and powder coating provide different color, gloss and texture controls.

Conductivity or insulation

Finish choice and masking must protect contact areas; anodic oxides are electrically insulating while selected platings can improve conductivity.

Cleanability & smoothness

Passivation, electropolishing and polishing are common review paths for suitable stainless-steel or metal parts.

Dimensional control

Coating growth, material removal and masking must be included in the tolerance plan before machining is released.

Finish-ready RFQ

Send the requirements that control the result.

Surface finishing can change dimensions, texture, color, conductivity and corrosion behavior. Define the acceptance criteria before the manufacturing route is released.

Request a Surface-Finish Review

Base material and exact alloyInclude temper, heat treatment and any restricted alternatives.
Applicable finish specificationState type, class, grade, thickness or performance requirement.
Masking and contact pointsIdentify threads, bores, sealing faces, electrical contacts and cosmetic zones.
Appearance acceptanceProvide RAL/Pantone, gloss, texture, sample and allowable variation when relevant.
Inspection and test scopeCall out thickness checks, adhesion, corrosion testing or certificates when required.

Frequently asked questions

Specify the finish before quotation.

Early clarification reduces rework around coating allowance, masking, color and inspection.

Prepare a complete RFQ

What is the difference between Type II and Type III anodizing?+

Type II is conventional sulfuric-acid anodizing and is commonly selected for corrosion protection and cosmetic color. Type III is hard anodizing and is normally thicker and more wear resistant, so coating allowance and masking become more important.

Is dyed anodizing the same as electrolytic coloring?+

No. Dyed anodizing uses dyes absorbed by the porous oxide. Electrolytic coloring deposits metal compounds in those pores after anodizing, typically producing a narrower bronze-to-black range with good outdoor color stability.

How is micro-arc oxidation different from hard anodizing?+

Micro-arc oxidation, also called plasma electrolytic oxidation, uses higher electrical energy and micro-discharges to form a ceramic-like oxide. It can create thicker, harder and rougher functional layers, but the final properties depend strongly on alloy, electrolyte and process parameters.

Should coating thickness be included on the drawing?+

Yes when it affects fit, wear, corrosion performance or inspection. Identify the applicable specification, thickness range, masked areas, critical dimensions and whether dimensions apply before or after finishing.

Can you match a RAL, Pantone or customer color sample?+

Share the color system, gloss or texture target and an approved physical sample when appearance is critical. Material, pretreatment, geometry and production lot can affect the final result, so acceptance criteria should be agreed during project review.

Are all finishes completed in-house?+

The manufacturing and finishing route is confirmed during project review. Depending on the process and specification, finishing may be coordinated with a qualified specialist supplier and verified against the agreed drawing and inspection requirements.

Discuss the right finish for your custom part.

Send the key project details and our manufacturing team will respond with a focused next step.

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