Which factors are related to the excessive surface particles during the powder spraying process of aluminum profile

In the process of powder spraying of aluminum profiles, a common problem that makes powder spraying technicians feel headache is the protruding particles-particles on the surface of the powder coating coating. The particles seriously affect the decorativeness of the surface coating of the aluminum profile. Regarding which factors are related to the excessive surface particles during the powder spraying process of aluminum profiles, let's take a look together.

 

 

1. Processing of coated aluminum profiles

 

When spraying, the surface of the painted workpiece should be polished as smooth and flat as possible, and the surface has no oxide scale and micropores. If possible, it can be pre-baked, which can also effectively reduce the formation of particles.

 

2. Surface treatment of workpiece

 

Generally, powder-coated aluminum workpieces need to go through the following process: shelf-degreasing-water washing-chromization -...-curing-unloading; among them, impurities such as chromium residues during the surface treatment process may adhere to the workpiece. This results in the presence of particles after film formation.

 

3. The surrounding production environment of the powder spraying room

 

The production environment around the powder spraying room will directly affect the surface quality of the coating film. For the coating of the electrostatic spray gun with corona discharge, some dust and particles in the environment are brought into the powder coating room and charged by static electricity. Impurities are adsorbed on the surface of the coating and become particles on the surface of the coating when the powder is melted and leveled. A clean production environment has a good effect on product quality.

 

4. Thickness control of coating film

 

For the spraying technicians, they all understand that if the coating film is too thin, in addition to particles, poor leveling, serious orange peel, and poor hiding power of light-colored varieties will occur. At the same time, the coating film is acid and alkali resistant. , Poor salt and water resistance. Appropriately increasing the thickness of the coating film can effectively reduce the formation of particles. The coating film should not be too thick. Generally, too thick will affect the size of the coated workpiece, and the performance of impact resistance, flexibility, and adhesion will decrease. It is normal for the thickness to be controlled at about 40~120um.