Adhesion Issues in Powder Coating: Causes & Solutions
A common issue in powder coating is poor adhesion of the powder layer. This results in an inferior finish and reduced corrosion resistance.
🚩 Root Cause Analysis
- Poor grounding of workpieces: Hangers and baskets must be clean and conductive – not oxidized or contaminated with powder residues.
- Inappropriate powder particle size: Coarse particles affect electrostatic charge and adhesion. GEMA recommends consulting powder suppliers.
- Incorrect airflow strength: Too high a field current or too low/high air pressure can weaken powder deposition.
- Air humidity above 80% RH: High humidity reduces electrostatic adhesion. A cooler, drier room is required.
🛠️ Practical Measures
- Optimize grounding: Clean hooks, baskets & conductive parts regularly (e.g., remove metal deposits).
- Check powder quality: Inspect particle size distribution – contact manufacturer if issues arise.
- Adjust field strength: If voltage is too high, increase the distance between gun and object.
- Regulate indoor climate: Use automatic climate control or separate powder zones in high humidity.
✅ Benefits of Optimization
- Significant improvement in coating quality
- Reduction of waste due to fewer rejects
- Increased process reliability and repeatability
🔗 Further Information
For more technical advice on adhesion and field settings, visit GEMA’s “Tips & Tricks” section under “Adhesion”.
