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Coating methods and precautions for metal powder spraying

2019-05-23
Coating methods and precautions for metal powder spraying
 
Webex automobil surface treatment: it is well known that in the process of metal powder spraying, powder coating after the fluidization by airflow conveying to the spray gun, spray gun by high-voltage electrostatic generator, the nozzle of the needle electrode produce corona discharge, near the electrode has a negative charge, through spear powder, capture charge become charged powder, under the action of electric field in the air, and its own gravity, flew to the ground workpiece, and adsorption on the material surface.Therefore, in our spraying process, we need to take adequate precautions.
 
 
Coating method of metal powder spraying
In most cases, it is the use of electrostatic spray gun spraying, because this type of products contain metal pigments, in the use of electrostatic gun spraying should ensure a good grounding system, while setting a low electrostatic voltage and powder amount, to prevent the occurrence of spark phenomenon during spraying.The effect of forming the film has a lot to do with the setting, quality or brand of the gun.There may be a large amount of metal powder accumulation in the spray gun in the electroacupuncture place after a long time of spraying, the need for regular cleaning electroacupuncture spraying.
 
Metallic powder coating luster
In most cases, due to the large error, it is not recommended to use the gloss meter to measure the gloss of the metal surface coating film, but only use the visual contrast method to determine whether it is consistent with the standard template.
 
Recyclability of metal powder coating
For powder manufactured by dry mixing, separation will occur in the process of spraying and recycling, so there will be a certain difference in the content of metallic pigment between the recycled powder and the new powder, which may lead to inconsistent appearance of the coating film and color deviation.This is due to the nature of the difference between metallic pigments and powder particles.Experts recommend that the ratio of recycled powder to new powder should be at least 1:4.If the powder coating manufactured by the adhesive fixation method is used, the recovered powder can be completely reused because the ratio between the metal pigment and the powder particles is relatively fixed.
 
Metal powder coating coating coating
The coating has the following advantages: it can enhance the anti-stoning performance of the metal powder coating;Increase the aesthetic effect of metal powder coating;Completely solve the metal pigment erasability;Improve the weather resistance of metal powder coating.In order to ensure the appearance of the coating, it is required that the workpiece after * times of spraying shall not be contaminated.Therefore, the general need for a full automation of the spray line and two sets of independent spray chamber for spray respectively.It is recommended that under normal circumstances do not spray coating.
 
The erasability of metal pigments
Neither the dry mixing method nor the adhesive fixation method can completely solve the problem of metal pigment's erasability.The solution is to spray a transparent coating on the metal powder coating.
 
Try to keep the spraying condition stable
Using the same set of spraying equipment, using the same voltage, air pressure and other parameters;Try to keep the distance between the spray gun and the workpiece unchanged, try to keep the stability of the film thickness;Ensure that the powder coating has been fully fluidized before spraying;When using recycled powder, the ratio of recycled powder to new powder should be less than 1:4;To avoid the use of metal powder coating coating complex shape or the presence of deep depression of the workpiece;It is recommended that multiple workpieces to be assembled together be sprayed simultaneously.