Fluorocarbon spraying process flow is:
Pre-treatment process: Degreasing of aluminum material → Washing → Caustic washing (degreasing) → Washing → Pickling → Washing → Chromizing → Washing → Pure water-washing Spraying process: Primer → Finishing → Varnishing → Baking (180-250°C)→Quality inspection Multi-layer spraying process with three sprays (three sprays for short), spray primer, topcoat and varnish, and secondary spray (primer, topcoat).
1. The purpose of the pre-treatment: Before the aluminum alloy profiles and plates are sprayed, the surface of the workpiece is subjected to oil removal and chemical treatment to produce a chromium film, which increases the binding force and oxidation resistance of the coating and the metal surface, and is advantageous for extending the paint. The useful life of the membrane.
2. Primer coating: As a primer coating for a closed substrate, its role is to improve the coating's resistance to penetration, enhance the protection of the substrate, stabilize the surface layer of the metal, and enhance the adhesion of the topcoat to the metal surface. The color uniformity of the paint coating, the thickness of the paint layer is generally 5-10 microns.
3. Topcoat: The topcoat is the key layer of the spray coating. It provides the decorative color needed for aluminum, which allows the appearance of the aluminum to meet design requirements, and protects the metal surface from the external atmosphere, acid rain, and pollution. To prevent UV penetration. The anti-aging ability is greatly enhanced. The topcoat is a thicker layer of paint in the spray coating. The thickness of the paint layer is generally 23-30 microns.
4. Cover varnish coating: varnish coating also known as varnish coating, the main purpose is to more effectively enhance the anti-corrosion ability of the paint layer, to protect the top coat, increase the color of the top metal gloss, the appearance of a more vivid color, Brilliant, coating thickness is generally 5-10 microns. The total thickness of the three spray layers is generally 40-60 micrometers, which can be thickened for special applications.
5. Curing treatment: three spray layers generally require secondary curing, aluminum into the curing furnace processing, curing temperature is generally between 180 °C -250 °C, curing time is 15-25 minutes, different fluorocarbon coating manufacturers, will be based on their own Coatings provide better temperature and time. The chlorocarbon spraying plant (the oyster plant) also had its own experience to change the two cures at the triple injection to a single cure.
6. Quality inspection: Quality inspection should be in accordance with AAMA-605.02.90 standard. Strict quality checks ensure high quality spray products.
Fourth, the current status of China's fluorocarbon spraying With the rapid development of China's construction industry in recent years, the rise of the curtain wall industry in China, aluminum requires a variety of colors, the rise of the aluminum curtain wall industry, especially in the realization that aluminum composite board is not easy to use After high-rise buildings, the demand for fluorocarbon sprayed coatings for single-layer aluminum panels and aluminum profiles in China has increased exponentially from the early 1990s. The original earlier only in Dongguan, Guangdong, there are two oil plants (that is, fluorocarbon spraying plant) from the beginning of 1995 to date, China has increased to more than 30, but also surrounded, there are manual and automated, the scale is large and small, many Built along the coast. Not only has a professional spraying plant been established, but individual aluminum plants and curtain wall companies have also invested in the construction of a spraying plant, which still maintains a small and complete system. There are only a dozen or so officially put into production with obvious quality differences.
New domestic fluorocarbon spraying equipment is mostly designed for the United States, Germany, Japan, and introduces computer software to introduce various types of electrostatic spray guns from various countries. Suspension type has semi-suspension type, pre-treatment of aluminum material, spraying, and curing process. All aluminum materials are suspended. Computer-operated workpieces are used for lifting and walking. Cleaning, multiple spraying, curing until the spray finished product. This kind of fully automatic line is not much domestic, and the investment is large. Another type of pretreatment for aluminum plates is performed in several baths (such as aluminum baths for anodic oxidation). The chromization is also carried out in the bath. The aluminum is then suspended and the workpieces are walked on the cradle. The spray curing process is completed until the product is released. The domestic hanging line is now 100 meters long and 420 meters long. General automatic fluorocarbon spraying is mostly used for the surface spraying of aluminum plates. Because the aluminum profile has a length of 6 meters, it is difficult to suspend and spray the automatic belt with a length of 6 meters. In early 90s, Hong Kong was established earlier in Dongguan, Guangdong. The former professional oyster sauce company called the successful professional oyster sauce company in Hong Kong, and built a new 420-meter-long automatic fluorocarbon spraying line in the country. It can not only spray aluminum plates of various specifications and thickness, but also Automatic spraying of six meters long aluminum profiles, annual spraying area of ​​600,000 square meters, is now a larger, longer, the profile plate are automatically sprayed a spraying line.
The advanced and backward products of any product and equipment are, of course, an important factor in product quality. However, the equipment is often seen as overweight, as if the equipment is good enough to produce a good product. This is not the case. Technology software is more important. Without high-level technicians and skilled workers, only good equipment can produce no satisfactory products. Just like a driver with low driving skills, driving a Mercedes-Benz car will also cause accidents. Fluorocarbon spraying technology is very strong, in the new domestic spraying line, the regular commissioning can be 2-3 months, but some debugging half a year or even longer time is not good, this does not explain the technical experience importance. In the near future, there was a cheap construction project, which caused a spraying plant that had just been tested to spray nearly 1,000 square meters of aluminum. The result was that the color difference was very large and the film thickness was uneven. Only a small part could be used, seriously affecting the completion date of the curtain wall, and urging users to When selecting a spraying plant, not only the advanced level of the equipment, but also the conditions and experience of the technicians must be emphasized. That is to say, software should also be valued.
In short: Fluorocarbon spraying is a relatively new product in our country. We need to understand it first to understand it and use it correctly. We hope that some new spraying lines in China will need to improve technology, sum up experience, and steadily develop fluorocarbon spraying. cause. There are more than 30 painting lines in the country, and the annual spraying area has exceeded 4 million square meters. Supply exceeds demand, do not repeat on the fluorocarbon spraying line for a short time.
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