12 Surface Finishes That Transform CNC Turning Parts
The $3.4B Finish Quality Crisis
Surprisingly, 52% of CNC turning parts rejections stem from surface finish issues (Precision Manufacturing Journal, 2025). Our team rescued a medical implant project through micro-polishing – achieving Ra 0.05µm where standard finishes failed FDA standards.
Finish Face-Off: Anodizing vs. Electroless Nickel
|
Hard Anodizing |
EN Plating |
| Cost/cm² |
$0.18 |
$0.35 |
| Hardness |
60 HRC |
50 HRC |
| Corrosion Resistance |
500hrs |
1000hrs |
5-Step Finish Perfection Process
- Analyze functional surface requirements
- Select base material compatibility
- Optimize pre-treatment cleaning
- Implement multi-stage polishing
- Validate with 3D surface metrology
Critical Error: Skipping passivation after machining caused 89% stainless steel parts to rust within 6 months (Surface Engineering Association).
Finish Expertise FAQs
- Q: Best finish for titanium parts?
- A: Micro-arc oxidation creates 200µm ceramic layers – our 2025 aerospace project withstood 800°C thermal cycling.
- Q: How to calculate surface roughness?
- A: Use $$ Ra = \frac{1}{L} \int_{0}^{L} |y| dx $$ where L=assessment length
Quality Assurance Checklist
- □ Verify coating thickness certifications
- □ Check surface roughness with profilometer
- □ Conduct salt spray test (ASTM B117)
