Introduction：
Aluminum profile electrophoresis refers to the process of forming a dense resin film on the surface of extruded aluminum alloy by placing it in the electrophoresis tank with a direct current. The electrophoresis tank is composed of acrylic resin, cosolvent, and pure water. The process of aluminum profile electrophoresis includes electrophoresis, electrolysis, electrodeposition, and electroosmosis. The characteristics of the aluminum profile after electrophoresis paint: acid and alkali resistance, anti-pollution, delay in the aging of aluminum profile, durable, bright luster, not easy to fade.
Electrophoresis Elements:
Electrophoresis is the same as conventional light and transparent electrophoresis. Anode electrophoresis is carried out under the action of direct current. Under the action of an electric field, the charged coating particles move to the coated workpiece, to precipitate the electrophoretic coating deposited on the surface of the aluminum profile and form a film. The difference lies in the type of coating and slightly different equipment.
Electrophoretic coatings include acrylic resins, melamine resins, pigments, solvents, neutralizing agents, additives, and other components. By thermal fixation in the viaduct layer of particles, the shape of the micro-concave coating during baking is essentially unchanged during baking and the appearance of the film is formed evenly. Extinction can be adjusted by the ratio of high gloss paint to low gloss paint.
For contour colors, the color of the product depends on electrolytic coloring due to the transparency of the coating. By adding the color paste to select the desired color aluminum profile, you can also add the color of the profile to the color, white, ivory, green, red, ash, etc. Of course, its surface quality is superior to spraying.
Performance of aluminum profile electrophoresis product:
1. High transparency and full size with special gloss and transparency, the coating has a high stereo effect, and the color of the substrate is obvious.
2. High hardness, when baked at 180℃ for 30 minutes, the hardness can reach 4 to 5 hours.
3. Good fluidity, strong film, and smooth film.
4. Strong binding force and permeability, coating everywhere, wet film and dry film has a strong binding force.
5. Good performance, under the baking temperature of 180℃~200℃, the workpiece does not change color, color resistance, and corrosion, the product color is durable and bright, and corrosion effect is ideal.
6. Good average electrophoretic effect, and the film is uniform and smooth, reaching 10-16 um at 90-200 V, with high efficiency and low power consumption.
7. Good resistance to impact and artificial sweat.
8. Can be used in aluminum, metal plating, precious metal accessories, lamps, and high-grade furniture surface protection.
9. Can be electrophoresed into a variety of colors: titanium, ordinary gray, pure black, and other colors. Due to the high screening rate of the matte electrophoretic coating film, the extrusion die pattern on the aluminum surface has a certain covering effect, and it also has a certain compensation effect for the color difference of the dyeing process.
Methods and techniques of electrophoretic coating:
1. Electrophoretic coating of general metal surface, the process as follows: Shelving - pretreatment - anodizing - electrolytic coloring - electrophoresis - curing - unloading - packaging - warehousing.
2. The substrate and pretreatment of the coating have a great influence on the electrophoretic coating. Castings are generally sandblasted or shot peening for rust removal. Cotton yarn is used to remove floating dust on the surface of the workpiece, and 80# ~ 120# sandpaper is used to remove debris such as steel shot on the surface. Iron and steel surface oil removal and rust removal treatment, the surface requirements are too high, phosphating and passivation surface treatment.
3. In the filter system, it is generally used the first stage filter which is a mesh bag structure with a pore size of 25 ~ 75μm. The electrophoretic paint is filtered by a vertical pump to a filter. Considering the change period and the quality of the film, the filter bag with a pore size of 50μm is the best. It can not only meet the quality requirements of the film but also solve the blockage problem of the filter bag.
4. The circulating quantity of the circulating system of electrophoretic coating directly affects the stability of the tank and the quality of the paint film. Increase the circulation amount, the tank liquid precipitation, and bubble reduction; However, the aging of the tank is accelerated, the energy consumption increases, and the stability of the tank deteriorates. It is ideal to control the cycle times of the tank 6 ~ 8 times /h, not only to ensure the quality of the film but also to ensure the stable operation of the tank.
5. With the prolonging of the production time, the impedance of the anode diaphragm will increase and the effective operating voltage will decrease. Therefore, according to the voltage loss in the production, the working voltage of the power supply should be gradually increased to compensate for the voltage drop of the anode diaphragm.
6. Ultrafiltration system controls the concentration of impurity ions brought into the workpiece to ensure the quality of the painting. In the operation of this system should pay attention to, the system should run continuously after the operation, and is strictly prohibited from an intermittent operation to prevent the ultrafiltration membrane dry up. The resin and pigment after drying are attached to the ultrafiltration membrane, which can not be cleaned thoroughly, and will seriously affect the permeability and service life of the ultrafiltration membrane.
7. Electrophoretic coating method is suitable for mass assembly line production process. The renewal cycle of the electrophoresis tank should be less than 3 months. Taking an electrophoresis production line with an annual output of 300 000 steel coils as an example, is very important for the scientific management of the tank liquid. Various parameters of the tank liquid should be tested regularly, and the tank liquid should be adjusted and replaced according to the test results.
8. For the quality management of the paint film, the uniformity, and thickness of the film should be checked frequently, the appearance should not be pinhole, flow hanging, orange peel, wrinkles and other phenomena, regular inspection of the adhesion of the film, corrosion resistance, and other physical and chemical indicators. The inspection period according to the manufacturer's inspection standards, each batch should be tested.
The advantages of electrophoresis:
1. High hardness coating up to 3H hardness, strong coating adhesion.
2. Higher corrosion resistance, weather resistance, and alkali resistance than anodized aluminum profiles.
3. Smooth and colorful surface, polished finished.
