Surface Finishing Services for Machined, Molded, and Fabricated Parts
Top Proto delivers surface finishing services for custom manufactured parts across our CNC machining, injection molding, sheet metal fabrication, and 3D printing operations. We apply a broad range of surface treatments — anodizing, powder coating, bead blasting, plating, painting, and polishing — to meet your functional, corrosion resistance, hardness, and appearance specifications. Every surface treatment is applied in-house and documented as part of your order record, with inspection confirming that coating thickness, adhesion, and appearance meet your requirements before shipment.
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Accepted File Types: STEP, STP, SLDPRT, STL, DXF, X_T, X_B, IPT, CATPART, PRT, SAT, 3MF, JT
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As Machined
Standard delivery condition for CNC machined parts. Surface roughness Ra 3.2 on standard cuts; Ra 1.6 achievable with fine finishing passes. Tool marks visible on machined faces. No additional cost or lead time.
Bead Blasting
Uniform matte or satin texture produced by propelling fine glass or ceramic media against the part surface. Removes tool marks, eliminates surface reflectivity, and prepares the surface for anodizing or painting. Compatible with aluminum, stainless steel, and titanium.
Brushed Finish
Unidirectional linear grain produced by abrasive belt or pad finishing. Produces a fine parallel texture on flat and cylindrical surfaces. Specified for aluminum and stainless steel panels, handles, and decorative enclosures.
Mirror Polish
Progressive mechanical buffing to Ra 0.1 or below, producing a highly specular surface. Specified for optical components, medical instruments, decorative parts, and mold cavity faces. Adds significant lead time and cost.
Anodizing Type II (Clear)
Standard anodizing producing a transparent aluminum oxide layer 10 to 25 micrometers thick. Maintains the natural silver appearance of the aluminum alloy while improving corrosion and abrasion resistance. Compatible with 6061, 6063, 7075, and 5052.
Anodizing Type II (Color)
Type II anodizing with dye bath in black, blue, red, gold, green, or custom color. Dye is absorbed into the porous oxide layer before sealing, producing a consistent, integrated color. Color uniformity depends on alloy composition and surface preparation.
Anodizing Type III (Hard)
Hard anodizing producing an oxide layer 25 to 75 micrometers thick at lower temperature and higher current density than Type II. Produces significantly higher surface hardness (400 to 600 HV) and improved wear resistance. Dimensions increase by approximately half the coating thickness.
Black Oxide
Chemical conversion coating for steel and stainless steel. Produces a black magnetite layer providing mild corrosion resistance and low surface reflectivity without significant dimensional change. Used for tooling, fasteners, and industrial components.
Zinc Plating (Electroplated)
Electrodeposited zinc coating 5 to 25 micrometers thick on mild steel parts. Provides corrosion protection through sacrificial action. Available with clear, yellow, or black chromate passivation over the zinc layer.
Nickel Plating
Electroless or electrolytic nickel plating for uniform coating on complex geometries. Improves corrosion resistance, surface hardness, and electrical conductivity. Electroless nickel provides more uniform thickness on recesses and internal surfaces.
Chrome Plating
Decorative and hard chrome plating for appearance, corrosion resistance, and surface hardness. Decorative chrome applied over a nickel undercoat. Hard chrome applied directly for wear-resistant industrial applications.
Passivation
Chemical treatment for stainless steel removing free iron from the surface and promoting a stable chromium oxide passive layer. Improves corrosion resistance in aggressive environments. No dimensional change. Specified for medical, food, and marine components.
Electropolishing
Electrochemical process removing a controlled material layer from stainless steel surfaces, reducing roughness and eliminating microscopic burrs. Improves corrosion resistance and surface cleanliness for medical, pharmaceutical, and food-contact components.
Powder Coating
Electrostatically applied dry powder cured under heat. Produces a hard, impact-resistant, corrosion-resistant surface layer in the full RAL color range. Gloss, semi-gloss, and matte finishes available. Typical coating thickness 60 to 100 micrometers.
Painting (Liquid)
Liquid paint applied by spray in primer and topcoat systems. Available in standard and custom colors with gloss, semi-gloss, and matte finishes. Used where powder coating is not suitable due to part geometry, temperature sensitivity, or color matching requirements.
DLC Coating (Diamond-Like Carbon)
Physical vapor deposition coating producing a hard, low-friction carbon layer 1 to 5 micrometers thick. Used for cutting tools, medical instruments, and precision components requiring extreme surface hardness and low coefficient of friction.
Our Surface Finishes
The following surface finishes are available at Top Proto across our manufacturing operations. Finish selection depends on your part material, operating environment, appearance requirements, and dimensional tolerance constraints.