Coating material aspect. Such as cast iron, cast aluminum pieces have sand holes, or hot rolled steel plate surface rough, have fine holes, etc., these conditions will make the coating prone to appear sand (particles) or volcanic pits. This is because when baking curing powder coating, powder coating melt flow makes the coated surfaces closed at ordinary times, as the coated temperature increases, the coated sand holes or pores of air pressure, melt flow flat coating to hog, if internal pressure is not broken drum coating to form sand (particles), when drum coating and coating cannot heal when formation volcanic crater.

The most fundamental measure to solve this problem is to ensure that there is no sand hole in cast iron and cast aluminum. The surface of hot milk steel plate is flat without oxide skin and pores. If the material selection can not be solved, from the aspect of coating process, will be preheated, the use of thermal spraying process can solve this problem; In addition, the process of spraying twice can also solve this problem, but these two methods are more troublesome, and also increase the cost of coating.

If it is difficult to solve from the powder spray coating factory, you can also ask the powder coating factory to cooperate to solve. When the material quality of the coating can not be solved, it is the most effective method to solve from the powder coating production formula.

From the point of view of the powder coating factory, you can add defoamer and other additives in the formula to reduce the surface tension of powder coating in the melt flow at ordinary times, so that the air is easy to escape from the coated material sand holes or pores, at the same time, the air gap (hole) after the escape from the air can quickly smooth without leaving traces. In some cases, it is also necessary to adjust the reactivity of the powder coating to slow down the curing rate of the powder coating, so that the pores after escaping from the air have enough time to fuse and level out, without leaving behind the coated sand (particles) or volcanic crater.

The surface treatment of the coating is not good, the phosphating residue and other impurities in the surface treatment liquid are still attached to the surface of the coating, and it is easy to produce particles or particles of the coating film during powder spraying. This problem can be solved as long as the residue in the phosphating solution is cleaned in time and the coating is cleaned in the washing process.

In electrostatic powder coating, the production environment around the powder spraying room is not clean, especially some dust and particles in the air are brought into the powder coating or powder spraying room, or because of electrostatic induction effect, charged impurities are adsorbed to be coated above, in powder coating melting flow usually, become the particles or particles in the coating film. This problem can be solved by separating the powder spraying room from the production workshop to prevent the dust and dirt from entering the powder spraying room, and at the same time, the air entering the powder spraying room can be seriously purified. If the friction charge electrostatic powder spray gun is used, the dust in the environment will not be electrostatic, in contrast, the coating is less likely to produce particles (particles) caused by dust and other impurities in the air.

Posted by: hannahgwendolyn at 09:45 AM | No Comments | Add Comment
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