Knowledge Base
CNC Part Surface Finishing Guide
Detailed overview of 7 common processes including anodizing, passivation, electroplating, and spray coating
Process Types
Four Major Surface Finishing Processes
Understand the characteristics, applicable materials, and film thickness parameters of common surface treatments to select the best solution for your parts.
Anodizing
- — Natural anodizing (silver-gray, wear and corrosion resistant)
- — Black hard anodizing (high hardness, abrasion resistant)
- — Color anodizing (decorative, multiple color options)
- — Chromate conversion (non-insulating, suitable for grounding)
Film Thickness
Film thickness: 5-25μm
Applicable Materials
Only applicable to aluminum and aluminum alloys
Passivation
- — Stainless steel passivation (3-5x improved corrosion resistance)
- — Zinc plating passivation (color / blue-white / black)
- — Chromium-free passivation (environmentally compliant)
- — Ready for assembly directly after passivation
Film Thickness
Virtually no dimensional change (<1μm)
Applicable Materials
Applicable to stainless steel and zinc-plated parts
Electroplating
- — Nickel plating (wear and corrosion resistant, bright surface)
- — Chrome plating (high hardness and abrasion resistance, mirror finish)
- — Zinc plating (cost-effective corrosion protection, white / color zinc)
- — Copper plating (undercoat or conductive applications)
Film Thickness
Coating thickness: 5-20μm
Applicable Materials
Consider coating impact on tolerance specifications
Spray Coating
- — Powder coating (thick film, impact resistant, eco-friendly)
- — Liquid spray painting (smooth surface, rich color options)
- — Plastic spray coating (abrasion and weather resistant, ideal for enclosures)
- — Fluorocarbon coating (ultra weatherproof, 20+ years outdoors)
Film Thickness
Film thickness: 40-120μm
Applicable Materials
Surface pretreatment required before spraying
Selection Principles
Surface Treatment Selection Principles
Select the right surface treatment process to balance protective effect, appearance requirements, and cost control.
Pretreatment First
Proper degreasing, rust removal, and activation are essential before any surface treatment.
Dimensional Allowance
For processes with film thickness (plating, coating), leave tolerance allowance in the design.
Material Compatibility
Different substrates support different surface treatments — verify before committing.
Environment Matching
Choose treatment grade based on the operating environment (indoor / outdoor / corrosive).
Not Sure Which Surface Finish to Choose?
Tell us your application scenario and material — we will recommend the most suitable surface treatment solution.