Overview & Key Highlights:
Enhance Appearance, Performance, and Durability
Surface Finishing Services
✓
Enhanced corrosion, wear resistance, insulation, & surface finish.✓
30+ finishing options for CNC, 3D printing, molding, & sheet metal.✓
ISO 9001:2015, RoHS, REACH compliance, with CMM, gloss, and roughness testing.✓
Aluminum, stainless steel, carbon steel, titanium, brass, copper, plastics, & composites.Explore All Capabilities
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Molding? The Complete GuideJuly 24, 2026
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We finish parts in-house, in the same facility that machined or molded them — there's no shipping to a third-party finishing shop and back, which is where dimensional drift and handling damage usually happen. The team that owns your tolerance also owns the coating thickness, so the two never fight each other.
frequentlyaskedquestions?
What is Surface Finishing?Surface finishing is any post-manufacturing process that modifies a part’s surface for corrosion protection, wear resistance, electrical conductivity, cosmetic appearance, or regulatory compliance. Sango applies finishes to aluminum, steel, stainless steel, titanium, copper, brass, and engineering plastics produced by CNC machining, sheet metal fabrication, injection molding, or 3D printingSango finishes parts in-house — no outsourcing to third-party finishing shops. This means your finish specification is controlled by the same team that machined or molded your part, maintaining dimensional accuracy and eliminating handling damage from inter-facility transport.
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Surface Roughness & Technical Specification TableRepresentative roughness levels (Ra) and dimensional tolerances for key finishing processes:
Surface Roughness (Ra)Finishing ProcessDimensional Thickness ChangePrimary Application / Benefit
As-Machined (Standard)
Ra 1.6 – 3.2 µm0 µm
Standard structural and internal mechanical components
Bead Blasting
Electroless Nickel Plating
Ra 1.6 – 3.2 µmMinimal (<2 µm)Uniform matte cosmetic finish, eliminates tool marks
Ra 0.4 – 1.2 µm
+5 to +25 µm
(completely uniform)
(completely uniform)
Uniform coating for complex internal cavity geometries
Ra 0.8 – 1.6 µm
+5 to +15 µm
(half penetrates metal)
(half penetrates metal)
Corrosion resistance, decorative color options
Unchanged
0 µm
(microscopic conversion layer)
(microscopic conversion layer)
Corrosion resistance without changing part dimensions
Anodizing Type III (Hardcoat)
Precision Polishing (SPI A-1)
Powder Coating
Ra 0.8 – 2.0 µm+25 to +50 µm
Extreme wear resistance, high hardness for heavy duty parts
Ra 0.012 – 0.05 µm
-1 to -5 µm removal
Optical lenses, mold cavities, high-cosmetic panels
Smooth to Textured
+50 to +120 µm
Heavy-duty outdoor and cosmetic enclosure protection
Anodizing Type II
Passivation / Chem Film
What Are the Most Common Surface Finishes at Sango?Each finish card includes Ra value, coating thickness, compatible materials, and typical applications.
BrushingBrushing creates a directional satin finish (Ra 0.4–0.8 μm) using 120–400 grit belts. Available in aluminum, steel, stainless steel, titanium, and brass. Ideal for electronics, appliances, and architectural hardware.
Black Oxide CoatingBlack oxide creates a 0.5–1.5 μm matte black coating with minimal dimensional change. Provides mild corrosion resistance and improved lubricity. Ideal for fasteners, gears, tools, and steel components.
Passivation ProcessPassivation removes free iron from stainless steel, forming a chromium-rich oxide layer. Enhances corrosion resistance without dimensional or finish changes. Ideal for medical, food-grade, and chemical applications.
PaintingLiquid paint applied by spray gun for custom colors and cosmetic top coats where powder coating isn't practical. Typical dry film thickness of 25–75 μm. Compatible with aluminum, steel, and most engineering plastics. Ideal for enclosures, brackets, and consumer-facing parts.
PolishingMechanical or vibratory polishing progressively removes tooling marks to reach a mirror or near-mirror finish (Ra down to 0.05 μm). Works on aluminum, stainless steel, brass, and copper. Ideal for mold cavities, reflectors, and visible cosmetic surfaces.
Alodine CoatingChromate conversion coating (Alodine / chem film) applied to aluminum, forming a thin conductive layer with minimal dimensional change. Improves corrosion resistance and paint adhesion while preserving electrical conductivity. Ideal for electronics housings and RF-shielded enclosures.
CNC Machining Materials
CNC Machining
Injection Molding
Sheet Metal Fabrication
3D Printing
Extrusion
Die Casting
Vacuum Casting
Wire EDM
3D Printing
±0.008″
Precision
1 day
Lead Time
SLA/MJF/SLS/SLM
Technologies
Nylon, resin, metal powder
Functional prototypes & end-use parts
Complex geometries, no tooling cost
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How Does SANGO's Surface Finishing Process Work, Step by Step?
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Upload your STEP, STP, STL, or IGES file with your finish requirements. Our engineers can recommend the best finish for your material, application, and appearance.Automated DFM Review
/01
Choose your finish, coating thickness, and target roughness for each face or callout. We confirm material compatibility and price the finish alongside your part.Select Finish & Confirm Quote
/02
Once your order is confirmed, the part is machined or moulded and moves directly to our in-house finishing line — no shipping to a third-party finisher and no added handling risk.In-House Finishing
/03Every finished part is checked for coating thickness, roughness (Ra), and color match before it ships, with inspection data available on request.Inspection & Shipment
/04
Automotive
Aerospace
Medical
Consumer Products
Robotics
Automation