Electrostatic powder spraying is the use of high voltage electrostatic corona electric field principle. The metal guide ring on the head of the spray gun is connected with the high pressure negative electrode and is grounded to the positive electrode by the coated workpiece. A strong electrostatic field is formed between the spray gun and the workpiece. When shipping carrier (compressed air) to pass through the duct powder for powder coating from the unit to the spray gun guide ring, due to the guide ring connected to high voltage anode produce corona discharge, the surrounding to produce dense and make the powder with negative charge, charge in electrostatic force and compressed air under the joint action of the two force, powder spray gun from the mouth to fly to the workpiece, and adsorb evenly on the workpiece surface, and dissolved by heating the powder a flat to a uniform, continuous, smooth, glossy coating.

The first stage: under the action of electrostatic electric field force, the powder evenly adsorbs on the surface of the workpiece, forming a thin continuous covering layer. In this stage, the powder is basically adsorbed by the workpiece.

The second stage: powder under the action of static electric field, continue to fly to the workpiece surface, because of has been covered with powder and powder in the same electric charge and produce new repulsion, but static electric field strength is stronger than the repelling force, powder will continue to adsorption, thickening of coating will continue, but there are some powder adsorbed on the surface and not drop down.

The third stage: with the continuous increase of coating thickness, the repulsive force increases. When it reaches the same with the electrostatic field force, the powder will no longer be adsorbed. At this time, the coating thickness will no longer increase, and the ejected powder will not be adsorbed completely.

Of course, powder coating in the current process also has some shortcomings, such as powder xu material can not be as liquid coating can be quickly changed color; Uneven powder on the edges and corners of the powder coating; Powder coatings can not be as easily obtained as solvent based coatings. High curing temperature required for powder coating; When the dust concentration of powder coating construction site is too high, there may be danger of dust fire and explosion.

Posted by: hannahgwendolyn at 09:53 AM | No Comments | Add Comment
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