Raw machined parts rarely meet final product requirements. Finishing enhances corrosion resistance, wear properties, appearance, and surface conductivity.
In Chinese manufacturing, finishing is often the differentiator between a cheap-looking part and a professional-grade product.
Process | Best For | Cost (CNY/kg) | Lead Time
--- | --- | --- | ---
Electroplating (Zn/Ni/Cr) | Corrosion resistance | ¥5-30 | 2-5 days
Anodizing (Type II/III) | Aluminum parts | ¥8-25 | 3-7 days
Powder Coating | Large parts, outdoor | ¥3-15 | 1-3 days
Chrome Plating (Decorative) | Consumer products | ¥15-50 | 3-7 days
Passivation | Stainless steel | ¥2-8 | 1-2 days
Polishing (Mechanical) | Visible surfaces | ¥5-20 | 1-3 days
1. For outdoor aluminum enclosures: Type III hard anodizing (40-60μm, ¥15-25/kg)
2. For indoor steel brackets: Yellow zinc plating (8-12μm, ¥5-10/kg)
3. For consumer product appearance: Brushed + clear anodizing (¥12-20/kg)
4. For medical/food parts: Electropolishing (¥5-15/piece)
Most Chinese finishers in Guangdong offer free sample testing — send one part for trial before committing to batch production.
Defect: Pitting — caused by contaminated bath, fix by filtration
Defect: Poor adhesion — pre-treatment skipped, ensure degreasing
Defect: Color variation — bath temperature uneven, use temp-controlled tank
Defect: White rust on zinc plate — insufficient passivation, request trivalent passivation