Defects and Solutions of Powder Coating on Aluminum Profile

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Firstly: Color Difference
Causes of defects:

1. Uneven coating thickness of aluminum profiles;
2. Not uniformtemperature distribution of theaging oven;
3. Simultaneous production of goods withdifferent materials, thicknesses, shapes and sizes;
4. Beforechanging the powder paint, the powder feeding device, spray gun, spray room and powder recovery are not be cleaned;
5. Color difference caused by poordistribution of powder and paint.

Solutions:

1. Ensure that the thickness of the coating film on the aluminum profile is uniform;
2. The temperature distribution of the agingovenis uniform;
3. Classify the goods according to the material, thickness, shape and size；
4. Clean all materials and devicesbeforechanging the powder paint;
5. Improve the quality of the powder and ensure that the L, a, and b of the powder are not much different and theirpositive and negative are uniform.

Secondly: The causes of impurities and particles
Causes:

1. Impurities causedin the agingoven;
2. Dust in the coating room, clothing fibers, equipment abrasives and fouling of the coating system;
3. Too many powder additives, poor dispersionof powder paints, too high temperature of powder making resulting that some of them are fixed and solid;
4. Damp powder agglomerated together resulting to poor spraying effect;
5. Too many particles and impurities on the aluminum profiles before surface treatment;
6. Too much recycled powder added and not sieved;
7. Too thincoating sprayed onthe aluminum profiles, too hard to cover their slight defects.

Solutions:

1. Thoroughly clean the curing oven’s wall;
2. Improve the quality of powders;
3. Improvethe warehouse condition, not allowed forexpired plastic powder, and to transform the coating equipment;
4. Clean up the aluminum profilesbefore spraying to reduce the burrs;
5. Add light recycled andsievedpowders;
6. Appropriately increase the coating thickness of aluminum profiles.

Thirdly: Causes of the poor powder rate:
Causes:

1. Too smallvoltage when spraying;
2. Too small resistance of the high-voltage generator and too largeoutput current;
3. Too largepowder coatingpressure;
4. Insulatedhook and too poor electrical conductivity;
5. Longdistance between the spray gun and the aluminum profiles;
6. Poorpowder performance.

Solutions:

1. Adjust the voltage within60-90KV;
2. Appropriately increase the resistance value of the resistor;
3. Appropriately lower the air pressure;
4. Regularly clean the hookfor excellentconductivity;
5. Properly adjust the distancebetweenspray gun and aluminum profiles; choose superior quality powders.