Edge burn-off during powder coating: causes and solutions
When powder coating, it is crucial that the powder is applied evenly across the entire surface to ensure a high-quality, long-lasting coating. However, problems often arise on sharp edges in particular – known as edge burn-off. This causes the coating to become thinner at the edges or to show unsightly marks.
Causes of edge burn
Edges have a higher electrical field concentration. This attracts more powder, which can lead to excessive powder build-up during application and a thinner layer after baking. The problem is further exacerbated by high voltage or incorrect application techniques.
Recommended solutions
- Reduce high voltage: Lowering the high voltage weakens the field concentration at the edge and makes the powder application more even.
- Use special edge powder: There are special powder formulations that have been developed for better edge coverage.
- Optimised gun guidance: The distance between the gun and the workpiece edge should be adjusted to achieve an even powder application.
- Consider geometry: If possible, edges should have small radii to reduce the Faraday effect and edge burn-off.
Conclusion
Edge burn-off is a typical challenge in powder coating, but it can be effectively reduced through a combination of optimised system parameters, adapted application technology and suitable powders. This results in high-quality, durable surfaces.
