Process technology: common problems of powder coating

Update:18 Dec,2020

Powder coating manufacturers and companies that use powder coatings have been constantly exploring powder coating coating technology. Powder coating and its coating technology is a new process and technology that has been rapidly developed in my country for more than ten years. It saves energy and resources, reduces environmental pollution, is simple in process, easy to realize automation, durable in coating, and recyclable. The characteristics of reuse, the following summarizes the common problems of powder coating coating.
1. Discoloration of paint film

Causes: 1. There is residual treatment liquid on the surface of the coating; 2. Over-baking, or volatile gas in the furnace; 3. Mixing of other colors of powder during construction; 4. The pigment of the powder coating itself is not resistant to high temperature or The resin is easy to yellow.

Solution: 1. Improve the pre-treatment method; 2. Develop appropriate baking conditions and purify the baking furnace; 3. Strengthen the cleaning before construction; 4. Replace qualified powder coatings.

Second, there are particles on the surface of the coating

Causes: 1. The surface of the painted workpiece is not clean; 2. The powder supply is uneven and the spray gun is not atomized; 3. The powder is too fine or the powder is damp and agglomerates, causing the spray gun to accumulate powder; 4. The painting site is not clean or sprayed There is powder dripping indoors; 5. The quality of recycled powder or powder coating itself is poor.

Solution: 1. Improve the quality of the workpiece substrate and strengthen the pretreatment; 2. Adjust the air pressure, check the deflector, and adjust it to the best point; 3. Control the powder size distribution, keep the powder properly, and prevent moisture; 4. Clean up the site , Purify the air; 5. After the recycled powder is sieved, the new powder is mixed and used, and the qualified powder is replaced.

Three, shrinkage

Causes: 1. Oil stains on the surface of the workpiece; 2. Water, oil, etc. in the compressed air, 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-treatment; 2. Strengthen the purification of compressed air before painting; 3. Thoroughly clean the environment and replace qualified powder.

Fourth, poor leveling or serious orange peel

Causes: 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 too high or too low; 4. The coating film is too thin or too thick; 5. The workpiece is poorly grounded; 6 .Different powders are mixed.

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 damp; 3. Adjust the appropriate curing conditions; 4. Control the thickness of the powder at 60-80 μm; 5. Regularly Clean up hangers; 6. Strictly clean up the powder spraying system and site before construction to avoid mixing powders of different types or different manufacturers.