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What are the common problems of powder coating

Update:04-08-2021
Summary:

Discoloration of paint film Cause: 1. There is residual […]

Discoloration of paint film
Cause:
1. There is residual treatment liquid on the surface of the paint.
2. Excessive baking or volatile gas in the furnace.
3. Mix powder of other colors during construction.
4. The pigment of the powder itself is not resistant to high temperature or the resin is easy to turn yellow.
Solution:
1. Improve the pre-processing method.
2. Establish proper baking conditions and purify the baking furnace.
3. Strengthen the cleaning before construction.
4. Replace qualified powder paint.
There are particles on the surface of the coating
Cause:
1. The surface of the painted workpiece is not clean.
2. Uneven powder supply and poor atomization of the spray gun.
3. The powder is too fine or the powder is damp and agglomerates, causing powder to accumulate in the spray gun.
4. The painting site is not clean or there is powder dripping in the spray chamber.
5. The recycled powder or the powder itself is of poor quality.
Solution:
1. Improve the quality of the workpiece substrate and strengthen the pre-treatment.
2. Adjust the air pressure and check the deflector.
3. Control the particle size distribution of the powder, keep the powder properly, and prevent moisture.
4. Clean the scene and purify the air.
5. After the recycled powder is sieved, the new powder is mixed and used, and the qualified powder is replaced.


Shrinkage
Cause:
1. There is oil stain on the surface of the workpiece.
2. The compressed air contains water, oil, etc., causing the powder to be contaminated.
3. Contaminated by dust or other impurities
4. The powder coating itself is contaminated
Solution:
1. Strengthen the pre-processing.
2. Strengthen the purification of compressed air before painting.
3. Thoroughly clean up the environment and replace qualified powder.
Poor leveling or serious orange peel
Cause:
1. The surface of the workpiece is rough
2. The powder particles are coarse, damp or the powder leveling itself is poor
3. The curing temperature is high or low
4. The coating film is too thin or too thick
5. Poor grounding of the workpiece
6. Mixing of different powders.
Solution:
1. Improve the finish of the workpiece.
2. Choose high-quality powder with uniform particle size distribution and good leveling, and prevent the powder from being damp.
3. Adjust the appropriate curing conditions.
4. Control the powder thickness in 60-80μm.
5. Clean the hanger regularly.
6. Strictly clean up the powder spraying system and site before construction to avoid mixing powders of different types or different manufacturers.

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