Characteristics Of Powder Coating Process For Aluminum Extrusions

With the continuous development of powder coating technology, electrostatic powder coating on the surface of aluminum profile is widely used by the current powder coating technology because of its unique advantages. The main features are that the recycling rate is up to more than 95%, does not pollute the environment, does not need preheating, powder coating can be carried out under normal temperature conditions, thick film can be formed at one time, and hanging flow will not occur, etc. Powder coating includes air spraying method, fluidized bed dip coating method, electrostatic fluidized bed dip coating method, electrostatic powder spraying method, flame spraying method and electric field corona spraying method.

Powder coated aluminum frame has a lot of applications, such as powder-coated aluminum window frames. Each coating method has different characteristics and applicable conditions. The following is a brief analysis of these coating methods and characteristics.

Air Spraying Method

Place the powder coating in the spray gun and use the adsorption force of compressed air to adsorb the coating on the surface of the pre preheated aluminum profile. The powder is melted on the surface of aluminum profile. Thermoplastic and thermosetting powder can be used. If it is thermosetting powder, it should be solidified in the oven. This spraying method is suitable for the surface of a small aluminum profile.

Electrostatic Powder Spraying

This is the most widely used powder spraying method at present. It uses the principle of electrostatic adsorption to make the powder coating induced by electrostatic carry opposite charges and adsorb to the surface of aluminum profile. Both thermal spraying and cold spraying can be carried out. After spraying, it needs to be dried in the baking furnace. This spraying method is suitable for the surface of aluminum profiles of different sizes and shapes. Both thermoplastic and thermosetting powders can be used.

Fluidized Bed Dip Coating Method

First preheat the aluminum profile and then immerse it into the powder coating fluidized bed to melt the powder to the surface of the aluminum profile. The thermoplastic and thermosetting powder can be used. If it is thermosetting powder, it should also be solidified in the oven. This spraying method is suitable for the surface of small aluminum profile with film thickness, as well as medium-sized pipelines or metal mesh, which can be dip-coated in an all-round way.

Electric Field Corona Coating Method

Place the thermoplastic or thermosetting powder between two parallel electrodes to make the powder coating charged. Pass the coated object between the electrodes to make its surface absorb the powder. A fluidized bed shall be placed under the device, and the spraying material shall be sprayed from the nozzle of the ejector, which is suitable for spraying (10-20) with a thin coating μ m) Small aluminum profile.

Impact Coating Method

This spraying method is also called mechanical spraying method. Powders with different particle sizes are mixed with glass beads in a certain proportion and sprayed by the nozzle of the ejector. The powder is deposited on the surface of aluminum profile under the impact of glass beads. This method is suitable for spraying thinner film (2-10) μ m) Aluminum profile.

Electrostatic Fluidized Bed Dip Coating

This spraying method combines the fluidized bed dip coating method with electrostatic powder spraying. Thermoplastic and thermosetting powders are used, which is suitable for film thickness of 150 μ m.