Precautions Of Powder Coating In Spraying Aluminum Profiles

Metal profiles are widely used in all aspects of buildings because of their excellent durability, decoration and processing formability. Aluminum profile accounts for more than 80% of metal profile because of its good processing performance and light weight. The application of powder coatings in aluminum profiles has increased rapidly. So what are the precautions of powder coating in spraying aluminum?

What Is Industrial Aluminum Profile Powder Coating?

Aluminum profile powder coating is actually a kind of powder spraying. That is to use powder equipment (electrostatic spraying machine) to spray painting powder-coated aluminum on the surface of aluminum profile or workpiece, and then under the action of static electricity, the powder will be evenly adsorbed on the surface of aluminum profile to form a powder coating, and then after high-temperature baking and leveling, it will become a coating with different effects. This process is called aluminum profile powder spraying.

The purpose of white aluminum profile powder spraying is to improve the adsorption force on the substrate surface of the industrial aluminum profile, increase the corrosion and oxidation resistance of aluminum profile surface, and improve the appearance quality and mechanical properties of aluminum profile. At the same time, it can also remove oil dirt, dust, and other sundries on the surface of the aluminum profile.

Precautions of powder coating in spraying aluminum

Two points to be noted before the production process of powder sprayed profiles:

Clamp

As a whole, there are two kinds of clamps, one is the clamp placed at both ends of the profile, and the other is the clamp placed at the middle part of the profile. The two are significantly different in application.

The clamps hung at both ends shall ensure that they can bear the pressure of considerable weight, because a connection mode similar to series connection is adopted in the feeding mode. Due to the influence of the self weight of the profile and the small contact area between the hanger and the profile, the hanger must maintain considerable bearing capacity;

The fixture used in the middle part should follow a basic principle in the process of manufacturing and use, that is, the size of the contact point between the fixture and the outer surface (i.e. surface) of the profile should be minimized. The contact point hinders the adsorption of powder on the surface of the profile and forms some small defects;

The larger the contact point is, the larger the area of the defect is. Therefore, the contact area of the fixture profile should be reduced as much as possible. In addition, the fixture at the middle part has a hanging rod placed vertically in the design, which adsorbs some powder in the production process and hinders the adsorption of powder on the rear profile. Therefore, these parts should be powdered in time.

The hanging position in the hanger of profile shall also follow the corresponding principles, including placing the complex surface in the horizontal position as far as possible, and the horizontal left and right sides are the places where the powder is most easily absorbed.

And the most complex side is inclined to the same direction as far as possible. At this time, the powder discharge amount and the pressure of compressed air on the inclined side can be appropriately increased, and the powder discharge direction is parallel to the groove, so the force is easy to absorb the powder.

For some profiles with deep grooves. Increasing the powder output and pushing the distance between the spray gun and the profile are applicable. The surface with large surface area or complex structure shall not be placed downward. At the same time, the decorative surface and non decorative surface of profile shall be distinguished.

In general, consumers' requirements for the decorative surface of profiles are often higher than those for non decorative surfaces, and the bite with walls and profiles can cover up some defects.

For some profiles with special shapes, adjust the position of the fixture in time to keep the profile at a certain inclination angle at the position of the hanger, so as to enhance the stability in the operation process and facilitate powder adsorption.

In addition, for some heavy profiles, when using the fixture in the middle position, the elbow part should have a certain radian, because when the weight is large, it will produce similar tail warping phenomenon, which is easy to fall off during operation. The radian of the fixture can ensure that the profile is in the vertical position and ensure the smooth production process.

In addition, with the increase of recycling times of conductive beams and hangers, the film will accumulate more and more. The coating itself is non-conductive, which will affect the conductivity of the conductive beam and hanger, and then affect the uniform distribution of powder on the surface of the profile. The coating on the conductive beam and hanger should be removed in an appropriate way.

Pretreatment

It is mainly degreasing and tanning, with low raw material consumption and relatively easy daily maintenance. What we should pay attention to in the pretreatment process.

In order to improve the production efficiency and reduce the energy consumption in the drying process, large material racks are used in the pretreatment process, and more profiles to be treated are loaded as much as possible. The gap and density between profiles are the first consideration in the pretreatment process.

For some soft profiles, the cross arm should be placed in the middle of the profile, and the groove part should be placed downward as far as possible, which is conducive to the evaporation of water.

When there is still water residue after the drying process, in order to avoid damaging the chemical film on the surface of the profile and the profile is easy to deform when the temperature is too high, it should not be baked in the furnace. It can be dried by cooling or air gun.

In addition, the profile must maintain a proper inclination angle when entering and leaving each slot and in the process of drip drying, but it is easy to cause part of the profile to slip. Thousands of steel wire mesh shall be bound at one end of the material rack as a preventive measure.