The method of coloring a large commercial fan

With the continuous popularization of HVLS fans, they have also been gradually applied in commercial settings such as large shopping malls, sports arenas, and waiting halls. However, compared to industrial HVLS fans, commercial fans have certain aesthetic requirements and often need to be colored according to different occasions. Although there are many methods for coloring fans, different coloring schemes have their own advantages and disadvantages. In this article, we will introduce several common metal surface coloring schemes used in the industrial fan industry.

The main parts that need to be colored for commercial fans are the fan blades and motor frames, both of which are typically made of aluminum. The natural color of aluminum is silver, and its surface is smooth, making it difficult to paint. Traditional oxidation coloring and sealing treatment can only produce colors such as silver, antique bronze, and gold, which cannot meet the requirements of commercial applications. Therefore, we will introduce the basic principles and processes of three coloring methods: electrophoretic painting, electrostatic painting, and powder electrostatic spraying.

Electrophoretic painting:

Electrophoretic painting is an advanced coating method that emerged in the 1960s. It is used as a post-treatment process for oxidation coloring to improve the corrosion resistance, weather resistance, and decorative surface of profiles.

1. Principle: Using oxidized and colored commercial fan components (fan blades, frames) as the anode (or cathode), and stainless steel as the cathode (or anode), they are placed in a solution of thermosetting water-soluble acrylic resin paint. Under the action of a direct current voltage of 150-200 volts, charged paint particles move toward the components, forming a layer of adhesive paint film on the surface. Electrophoretic painting involves complex physical, chemical, and electrochemical processes, including electrolysis, electrophoresis, electrodeposition, and electrophoresis.

2. Process: Degreasing - rinsing - alkali etching - rinsing - neutralizing - rinsing - anodizing - rinsing - electrolytic coloring - rinsing - electrophoretic painting - rinsing - drying.

Electrophoretic painting process characteristics:

1. The paint is water-soluble, saving a large amount of organic solvents, reducing air pollution, and ensuring safety as there is no fire hazard.
2. The film thickness is uniform and can be quantitatively controlled by changing the electrical parameters. It can cover areas that are difficult to treat with general construction methods, such as the internal cavity and grooves of commercial fans.
3. High coating efficiency, low paint loss, and strong adhesion of the paint film.
4. High production efficiency and easy realization of automated production.

Electrostatic painting:

Electrostatic painting is developed from traditional spray painting technology combined with high-voltage electrostatic generators.

1. Principle: In a strong DC electric field, the object to be painted is the anode, and the spray gun is the cathode. After the paint is sprayed out from the gun, it becomes negatively charged through electrostatic discharge and is uniformly adsorbed onto the surface of the commercial fan component under the action of compressed air and static electricity. The paint layer is formed after drying.

2. Process: Degreasing - rinsing - alkali etching - rinsing - neutralizing - rinsing - chemical oxidation - rinsing - drying - spraying - curing.

Electrostatic painting process characteristics:

1. It significantly improves the utilization rate of paint.
2. It is easy to automate, reduces the labor intensity of operators, improves the working environment, and enhances labor productivity.
3. It can achieve good coverage on the convex, concave, and angular parts of the object.

Powder electrostatic spraying:

1. Principle: In a strong DC electric field, resin powder is sprayed out through a gun and becomes negatively charged through corona discharge. The charged powder particles are uniformly adsorbed onto the surface of the commercial fan component under the action of airflow and electrostatic attraction, and then heated and cured to form a film. The principle of powder electrostatic spraying is almost the same as that of traditional electrostatic painting with solvent-based coatings (especially using air-assisted electrostatic spraying methods), except that only powder dispersion exists without atomization.

2. Process: Degreasing - rinsing - alkali etching - rinsing - neutralizing - rinsing - chemical oxidation - rinsing - drying - spraying - curing.

Powder electrostatic spraying process characteristics:

1. Solvent-free, reducing pollution, lowering costs, and enabling recycling.
2. Excellent film quality, using various resins to obtain a wide range of high-performance coatings. The film is dense and not prone to defects such as pinholes.
3. Low paint loss, greatly improving paint utilization.
4. High work efficiency, easy process, and equipment control, suitable for batch production and continuous operation, and easy realization of automated coating.
5. Bright colors, with more than a hundred colors available according to requirements, and the color change is easier compared to electrostatic painting.
6. Good adhesion on the top and end of the object.

In summary, electrophoretic painting provides excellent corrosion resistance, weather resistance, and decorative surface for commercial fans suitable for outdoor use. Powder electrostatic spraying offers a variety of colors, uniform color distribution, excellent adhesion, corrosion resistance, and weather resistance. It can also conceal surface defects of profile materials, making it the mainstream coloring process in the market for commercial fan applications.