The surface of the workpiece needs pretreatment before using the plastic spraying equipment

Tuoshen surface treatment shares that many metal parts will inevitably get greasy and dirty in one way or another during their manufacturing process. Some metal materials, such as aluminum plates for rice gold, are packed with butter paper when they are taken out of the warehouse. Some steel plates or copper alloy parts are exposed to water vapor or corrosive gases due to welding or heat treatment and other processes; Some parts, profiles and even the whole table are seriously rusted. It is not easy to spray powder if the workpiece without surface treatment is directly sent to spray plastic. Even if some plastic can be sprayed, the plastic layer will fall off quickly. Therefore, the surface of any metal part must be pretreated before spraying with the plastic spraying equipment, otherwise the bonding force between the plastic layer and the metal will be affected.

The purpose of surface pretreatment is to:

1. Remove all kinds of oil stains and rust on the surface of parts, make them clean, and let the metal surface directly combine with the plastic layer, which is the most basic requirement to ensure the adhesion and the quality of the plastic layer.

2. The metal surface is roughened by sandblasting or chemical treatment, further enhancing the bonding force between the plastic layer and the metal surface, improving the protection performance and extending the service life.

The quality of surface treatment in powder spraying will directly affect the service life of the plastic layer. Mechanical sand blasting, chemical treatment and manual decoy can be used for surface treatment. In terms of adhesion, sand blasting is the best, followed by manual rust removal. But manual derusting is labor-intensive. Recently, most of the units that use plastic electrostatic spraying mainly use sand blasting, but also have chemical treatment tanks, because for thin-walled boxes or soft metal workpieces, the method of sand blasting can easily deform the workpieces, cause improper operation, and even break through the workpieces. In this case, chemical treatment must be used.

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