Reasons for powder coating sagging

Powder coating sagging refers to the uneven flow of powder on the surface of the coated part during the coating process, forming a sag or sagging phenomenon. Sagging may cause problems such as uneven coating thickness and poor surface quality. The following are some reasons that may cause powder coating sagging:

1. Properties of powder coating: -High viscosity: High viscosity of powder coating may lead to poor fluidity and increase the risk of sagging. -Excessive particles: Excessive particles may make it difficult for the powder to be evenly distributed during the spraying process, and it is easy to form sagging.

2. Spraying equipment problems: -Nozzle blockage: Nozzle blockage will cause uneven spraying of powder and cause sagging. -Improper spray gun debugging: Improper setting of spray gun debugging parameters (such as powder spraying air pressure, powder spraying current) may cause sagging.

3. Coating environment problems: -Excessive humidity: High humidity will cause powder to absorb moisture, increasing the risk of sagging. -Unstable temperature: Changes in temperature may cause changes in the fluidity of the powder, affecting the coating effect.

4. Preparation problems of coated parts: -Surface oil stains: Oil stains on the surface of the coated parts may hinder the adhesion of powder and cause sagging. – Rough surface: A rough surface may cause uneven powder adhesion, increasing the possibility of sagging.

5. Overspraying problem: – Too long spraying time: Excessive spraying time may cause the powder layer to be too thick, increasing the risk of sagging.

6. Storage and use of powder coatings: – Improper storage of powder: Improper storage for a long time may cause the powder to agglomerate, absorb moisture, and affect the coating effect. – Expired use: Using expired powder coatings may cause sagging and other problems.

Solving the problem of powder coating sagging requires comprehensive consideration of the above factors and systematic inspection and adjustment. Usually, the sagging problem can be improved by optimizing the spraying equipment, adjusting the spraying parameters, ensuring the stability of the coating environment, and preparing the surface of the coated parts. In actual operation, it is recommended to follow the technical specifications of powder coating and debug and improve according to the specific situation.

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