First of all, it's not a big deal, don't worry about it, okay
Whether in the laboratory or in the spray shop of the factory, powder dropping or low adsorbability between the powder and the workpiece after spraying is a common problem. Experienced sprayers encounter such problems, casually play with a few spray gun or adjust the voltage, or control the spray flow, the problem is always solved, but for those novice, these problems are a problem.
Here is the guide to guide the building owner, about the adsorbability between powder coating powder and spraying workpiece is poor or easy to drop the powder after spraying reasons and treatment methods ~
The reason:
1, no high pressure or insufficient high pressure;
2. The workpiece and electrostatic generator are poorly grounded;
3, the air pressure is too high, the powder is too violent;
4, the spray gun is too far away from the workpiece;
5. The air pumping volume of the spraying room is too large;
6. The internal Angle of the workpiece has electrostatic shielding effect;
7, the surface of the workpiece has an insulating layer;
8. Poor distribution of powder particles.
Problem Handling:
1. Repair electrostatic equipment or adjust voltage; 2. Check all ground points. 3, adjust the air pressure of the spray gun; 4. Adjust the position of the spray gun; 5, reduce the air suction volume; 6, adjust the voltage, air flow or use friction gun; 7, out insulation layer; 8. Replace the powder with good quality.
Four methods to increase the powder loading rate of powder coating
(1) Control the particle size distribution of powder coating powder, the narrower the better: reasonable control of powder particle size (more difficult), in our actual production only adjust the speed of ACM main and auxiliary grinding. Powder particle size is important 40-50um is appropriate, the narrower the distribution is the better.
② Improve the resin content: Improve the resin to decrease the amount of filler, select well charged resin, epoxy powder is better, some manufacturer on polyester powder, some manufacturer on polyester powder is more difficult (separate will grind epoxy, polyester jet plate), friction gun jet flow obviously better than static gun, and friction to squirt gun thicker coating, coating without the disadvantage of high pressure gun, such as hair flower big orange peel phenomenon.
③ Reasonable selection of fillers: fineness and dispersion of fillers are closely related to the powder. The precipitation powder is higher than that of normal ultrafine heavy barium, and barium sulfate is better than that of calcium carbonate.
(4) Increase the charged agent: in the formula to add the right amount of conductive agent (action mechanism: can make the powder particles with more charge. There is a strong electric field in the area between the high-pressure electrostatic spray gun and the workpiece, and the air is ionized to generate hundreds of millions of ions. When the powder particles of the electrifying agent pass through this area, they are polarized, and it can capture more negative ions and bring more charge. For the dead corner of the groove and other parts because the Faraday effect power line is weak, then the powder particles with more charge can reach the surface of the workpiece by their own power, so as to improve the powder of these parts.