Überbeschichtung in der Pulverbeschichtung: Ursachen, Risiken und Lösungen

Over-coating in powder coating: causes, risks and solutions

An excessive layer of powder can lead to a variety of problems, from poor adhesion to visual defects. This problem occurs frequently, especially with complex geometries or incorrect application settings.

Common causes of overcoating

• Excessive powder output: Incorrectly set feed rates or excessive material throughput.
• Lack of control over the layer thickness: insufficient measurements and checks during the coating process.
• Distance to spray gun too small: an incorrect spraying distance can lead to localised material build-up.
• Insufficient experience of the operator: manual errors due to uneven movement or incorrect parameters.
• Electrostatic charge: Excessive charge can cause too much powder to adhere to the surface.

Consequences of over-coating

An excessively thick layer of powder can have several negative effects:

• Poor adhesion: If the layers are too thick, they tend to peel off under mechanical stress or temperature fluctuations.
• Cracking: Stress cracks can occur during the firing process.
• Waste of material: higher powder consumption leads to unnecessary costs.
• Uneven surface structure: a thick layer can affect the desired surface.

How to avoid overcoating

To prevent overcoating, you should take the following measures:

• Correct adjustment of the powder quantities: Reduce the material throughput at the control unit.
• Optimisation of the spraying distance: Keep an even distance between the gun and the workpiece.
• Use of precise equipment: modern powder coating systems from Gema, Wagner and Nordson offer precise control of the powder quantity.
• Regular layer thickness measurement: Use layer thickness gauges to ensure an even coating.
• Training for operating personnel: Regular training in the optimal use of the systems reduces errors.

The targeted use of modern technologies and precise control allows an optimal powder layer to be created without wasting unnecessary material or risking quality issues.