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(1) Pretreatment. The surface pretreatment process is generally degreasing and chemical conversion. Degreasing is generally treated with special degreasing agents, whose purpose is to remove the grease, dirt and debris attached to the surface of the aluminum profile during the extrusion process, and to remove the oxide film on the surface of the profile. Chemical conversion treatment is generally chromified or phosphorus-chromified treatment, the purpose of which is to form a layer of chemical conversion film (such as chromified film or phosphorus-chromified film) on the surface of the substrate to enhance the adhesion between the substrate and the coating, and to protect the substrate.
(2) Drying treatment. The purpose of drying is to remove the water carried by the pretreatment process. There are generally two ways of drying, one is natural drying, and the other is high temperature drying. Natural drying, long drying time, low efficiency, enterprises rarely use; Most enterprises are using high temperature drying. High temperature drying should control the drying temperature, the general drying temperature after chrome treatment should not be higher than 65℃. The drying temperature of phosphate-chromium treatment should not be higher than 85 ° C. If the temperature is too high, the chemical conversion film will lose too much water and be destroyed.
(3) Powder coating treatment.
Electrostatic powder treatment
Electrostatic powder treatment is applied the powder to the surface of the aluminum alloy profile through the powder spraying gun to form a protective and decorative organic polymer film. It is to apply negative high pressure to the spray gun and ground the workpiece to form a high voltage electrostatic field between the spray gun and the workpiece.
Electrostatic liquid spraying process
Electrostatic liquid spraying process is to apply liquid coating to the surface of aluminum alloy profiles by electrostatic spraying gun to form a protective and decorative organic polymer film. For acrylic paint spraying and polyester paint spraying, it is generally brush coating, that is, to form a layer of paint film, and fluorocarbon paint spraying generally requires two, three or four coating treatments.
