Powder coating diversified coating

Powder coating is a common coating method. There are various methods of powder coating. Do you know the methods and characteristics of powder coating?

1. Electrostatic powder spraying method

In the electrostatic powder spraying method, the workpiece is generally grounded, the spray gun is equipped with a negative high piezoelectric, and the loaded powder particles fly to the grounded workpiece to be coated under the action of the electrostatic field to achieve a uniform coating. It is then leveled in a curing oven to form a uniform film. The remaining powder during the spraying process is recovered through the powder recovery device and reused. This powder coating method is widely used. for future development direction.

It is characterized by:

The uniformity of the coating film is better and the loss of powder is less. When applying the paint in a cold state, it can generally reach about 100 microns in one spray.

2. Powder electrophoresis method

The powder electrophoresis method is to disperse the resin powder in the electrophoretic paint and attach it to the surface of the workpiece according to the electrophoretic coating method. During baking, the resin powder and the electrophoretic paint base material are integrated to form a coating. It has the advantages of electrophoretic coating. For example, the deposition time is short, the production efficiency is high, the film thickness is uniform, and the thickness is easy to adjust by voltage. In addition, the common dust problem of powder coating is avoided. The disadvantage of this method is that due to the effect of moisture, the coating will produce pores during baking, and the baking temperature is high; in addition, the coating is thicker than ordinary electrophoretic paint, generally 40~100m.

3. Fluidized bed method

The fluidized bed method is to preheat the workpiece to a temperature above 20°C higher than the melting temperature of the powder, and then immerse it in the ebullating bed to partially melt the powder and adhere to the surface, and then fuse it to form a complete coating. The fluidized bed method is only suitable for thick-walled small workpieces with large heat capacity, and is not suitable for thin plate parts with small heat capacity. The higher the workpiece preheating temperature, the thicker the coating, generally between 100 and 300m. To form a thin coating below 100m, the fluidized bed method is not suitable. In addition, during fluidized bed coating, since the resin is heated to a high temperature and for a long time, water is often used for forced cooling after baking to reduce thermal decomposition.

4. Electrostatic fluidized bed method

The electrostatic fluidized bed uses electrostatically adsorbed powder on cold workpieces in a fluidized bed, so the workpiece does not need to be preheated and can form a complete thin coating, but it is only suitable for painting small parts.

The electrostatic field is introduced on the basis of the fluidized bed, which is a combination of the fluidized bed powder coating method and the electrostatic coating method.

5. Flame injection method

The flame spray method is rarely used because the resin is susceptible to high temperature decomposition and the coating film quality is poor.