Cautions for metallic powder coating

As we all know, in the process of powder coating, the powder is transported to the spray gun after fluidization through the air stream, the spray gun the electrode needle in the nozzle produces corona discharge with the high voltage electrostatic generator, and produces a dense negative charge near the electrode. When the powder is sprayed from the gun head, the charge is captured as a charged powder, which flies to the grounded workpiece under the action of the air stream, electric field and its own gravity,and adsorbed on the surface of the workpiece. Therefore, we need to take adequate preventive measures in the coating process.

Metallic powder coating in most cases, use electrostatic spray gun , because this type of product contains metal pigments,should ensure that the system is well grounded, while setting a low electrostatic voltage and powder output, to prevent the occurrence of ignition during spraying. The effect of forming the film has a lot to do with the spray gun setting, quality or brand of the spray gun. After spraying for a long time, a large amount of metal powder may accumulate at the discharge needle of the spray gun, which needs to be cleaned regularly.

In most cases, due to the big tolerance, it is not recommended to use the gloss meter to measure the gloss of the metallic  film, and adopt visual comparison method to determine whether it is consistent with the standard template.

For the powder manufactured by the dry mixing method, due to the separation phenomenon in the spray and recovery process, there will be a certain difference in the metal pigment content of the recovered powder and the new powder, which may lead to the inconsistent coating film and the color difference. This is due to the difference of properties between metallic pigments and powder particles. It is recommended that the ratio of recycled powder to new powder at least 1:4. If the powder manufactured by the bonding fixation method, the recycled powder can be fully reused because the ratio between the metal pigment and the powder particles is relatively fixed.

The following advantages can be obtained by spraying the high glossy clear coating layer on the metallic powder film: enhance the rock impact resistance ,increase the aesthetic effect,completely solve the erasability of metal pigments,improve the weather resistance. In order to ensure the coating film appearance, it is required that the first time sprayed  workpiece can not be contaminated . Therefore, it is generally necessary to have a fully automated coating line and two sets of independent spray booths for separated coating. It is recommended not to spray the high glossy clear coating if you don’t have the equipment and conditions.

The following advantages can be obtained by spraying the high glossy clear coating layer on the metallic powder film: enhance the rock impact resistance ,increase the aesthetic effect,completely solve the erasability of metal pigments,improve the weather resistance. In order to ensure the coating film appearance, it is required that the first time sprayed  workpiece can not be contaminated . Therefore, it is generally necessary to have a fully automated coating line and two sets of independent spray booths for separated coating. It is recommended not to spray the high glossy clear coating if you don’t have the equipment and conditions.