Five major processes of aluminum profile surface treatment
The production of aluminum alloy door and window profiles can be divided into four processes: ingot preparation, extrusion, heat treatment and surface treatment. With the continuous improvement of people's living standards, the requirements for the appearance color of doors and windows are getting higher and higher, and with the gradual refinement of aluminum processing technology, some complex surface treatments have been vigorously developed. The aluminum surface treatment processes we often see include electrophoresis, anodizing, fluorocarbon coating spraying, etc.
1. Electrophoresis Electrophoresis is the electrophoretic coating at the cathode and anode, under the action of voltage, the charged paint ions move to the cathode and form insoluble substances with the alkaline action on the surface of the cathode, which are deposited on the surface of the workpiece. Aluminum profile electrophoresis refers to the process of placing the extruded aluminum alloy in the electrophoresis tank, and forming a dense resin film on the surface after direct current is applied. The electrophoretic aluminum profile is very bright and has a mirror effect, which also improves the corrosion resistance. Process flow Electrolysis (decomposition) ➤ Electrophoresis (swimming, migration) ➤ Electrodeposition (precipitation) ➤ Electroosmosis (dehydration)
2. Anodizing Anodized aluminum profile refers to the process of forming an oxide film on aluminum products (anodes) due to the action of external current under the corresponding electrolyte and specific process conditions. However, the oxide film formed by the appearance of anodized aluminum is different from the general oxide film, and anodized aluminum can be dyed by electrolytic coloring. In order to overcome the defects of aluminum alloy surface hardness, wear resistance, etc., expand the application range and prolong the service life, surface treatment technology has become an indispensable link in the use of aluminum alloy, and anodizing technology is currently the most widely used and most successful. Process flow Degreasing ➤ Chemical polishing ➤ Acid corrosion ➤ Stripping black film ➤ Anodizing ➤ Dyeing pretreatment ➤ Dyeing ➤ Sealing ➤ Drying The difference between anodizing and electrophoresis: anodizing is oxidation first and then coloring, and electrophoresis is direct coloring.
3. Electrostatic powder spraying Spraying powder coating to the surface of the workpiece with electrostatic powder spraying equipment, under the action of electrostatic electricity, the powder will be evenly adsorbed on the surface of the workpiece to form a powdery coating, and the powdery coating is leveled and cured at high temperature to become the final coating with different effects. The spraying effect far exceeds the painting process in terms of mechanical strength, adhesion, corrosion resistance, aging resistance, etc. Process flow Surface pretreatment ➤ Spraying ➤ Baking and curing
4.fluorocarbon spraying Fluorocarbon spraying is a kind of electrostatic spraying, but also a liquid spraying method. The fluorocarbon spray coating used is a coating made of polyvinylidene fluoride resin baking as the base material or with metal aluminum powder as the pigment. There are suspended and semi-suspended, and the hanging type is the pre-treatment and spraying of aluminum, and the aluminum is suspended during the curing process. The high-quality fluorocarbon coating has a metallic luster, bright color and a clear three-dimensional effect. Process Pretreatment process: degreasing and decontamination of aluminum ➤ Washing ➤ Alkali washing (degreasing) ➤ Washing ➤ Pickling ➤ Washing ➤ Washing ➤ Chromization ➤ Washing ➤ Pure washing Spraying process: spraying primer ➤ Topcoat ➤ Overprinting ➤ Baking (180-250 °C) ➤ Quality inspection The difference between electrostatic powder spraying and fluorocarbon spraying: powder spraying is to spray powder coating to the surface of the workpiece with powder spraying equipment (electrostatic spraying machine), and under the action of electrostatic electricity, the powder will be evenly adsorbed on the surface of the workpiece to form a powdery coating. Fluorocarbon spraying is a kind of electrostatic spraying, which is also a liquid spraying method, called fluorocarbon spraying, and curium oil in Hong Kong.
5. transfer wood grain
Wood grain transfer profile refers to the wood grain pattern on the transfer paper or transfer film on the basis of powder spraying or electrophoretic painting, according to the principle of high temperature sublimation heat penetration, through heating and pressure, the wood grain pattern on the transfer paper or transfer film is quickly transferred and penetrated into the profile that has been sprayed or electrophoresis. The wood grain profile produced has a clear texture and strong three-dimensional sense, which can better reflect the natural feeling of wood grain, and is an ideal energy-saving and environmentally friendly material to replace traditional wood. Process flow Select the substrate ➤ Wrap the wood grain printing paper ➤ Cover the plastic bag ➤ Vacuum ➤ Bake ➤ Tear off the printing paper ➤ Clean the appearance