Introduction of aluminum surface treatment process

For aluminum, the colors that can be achieved by anodizing are indeed limited, usually silver, bronze, titanium, K gold or black. As for sometimes seeing that a lot of other colors are processed by other methods:
1. Electrophoretic coating

On the basis of anodic oxidation, through the effect of electrophoresis, a layer of water-soluble acrylic paint film is evenly covered on the oxide film, so that a composite film of anodic oxide film and acrylic paint film is formed on the surface of the profile. The hand feels smooth and delicate, and the appearance is bright and beautiful. In addition to the original oxidation coloring, it can produce more bright colors such as white and green.

For aluminum, the colors that can be achieved by anodizing are indeed limited, usually silver, bronze, titanium, K gold or black. As for sometimes seeing that a lot of other colors are processed by other methods:

1. Electrophoretic coating

On the basis of anodic oxidation, through the effect of electrophoresis, a layer of water-soluble acrylic paint film is evenly covered on the oxide film, so that a composite film of anodic oxide film and acrylic paint film is formed on the surface of the profile. The hand feels smooth and delicate, and the appearance is bright and beautiful. In addition to the original oxidation coloring, it can produce more bright colors such as white and green.

2. Color powder coating

A total of more than 200 colors to choose from, give designers a broad space, stable performance, strong paint film adhesion, not easy to peel off, acid resistance, salt spray resistance, mortar resistance, weather resistance, aging resistance and other excellent properties. The coating is non-volatile, non-oxidizing, non-polluting and harmful in the air, and has good environmental performance. The dirt on the surface looks new after washing

3. Color fluorocarbon spraying

The polyvinylidene fluoride paint coating is sprayed on the surface of the aluminum alloy substrate by static electricity. The fluorocarbon coating is vinylidene fluoride, fluorocarbon coating. Therefore, it can have long-lasting color retention, anti-aging, anti-corrosion, and anti-air pollution. Its fluorocarbon bond is one of the strongest molecular bonds and is superior to its polymerized molecular structure. Fluorocarbon spraying is used as a high-end surface coating process. More than 160 kinds of rich colors are enough to provide endless design space for architects and designers. It has the advantages of uniform color and excellent resistance to fading and staining.

Wire drawing has nothing to do with surface oxidation. Wire drawing should be done before oxidation; in addition, natural oxidation is definitely not possible. The surface obtained by natural oxidation should be called a quality defect. Its oxide film and specially treated oxide film composition , The appearance is completely different.

Another point is that coloring is not a post-treatment of oxidation, but is carried out at the same time as oxidation. The following oxidation coloring treatment methods are commonly used:

Colored anodized film

The aluminum anodic oxide film is colored by adsorption of dyes.

Spontaneous color anodic oxide film

This anodic oxide film is a kind of colored anodic oxide film spontaneously generated by the alloy itself under the electrolysis of a certain specific aluminum material in a certain suitable electrolyte (usually based on organic acid).

Electrolytic coloring

The coloring of the anodic oxide film is colored by electrodeposition of metal or metal oxide through the voids of the oxide film.

The coloring is indeed carried out simultaneously with the oxidation, but it is indeed called the post-treatment of the process, which means that it is carried out in addition to the process (it does not work).

The expression method of anodizing coloring is HYZX (X represents a specific color), and the decimal point divides it into three parts. The first part is the plating method (H represents the chemical method), and the second part represents the plating characteristics (Y oxidation) , The third part represents post-processing (ZX coloring). See GB1238-76 for details (I wonder if there is an updated national standard).

Ordinary anodizing (no coloring) is expressed as H.Y.

The drawing anodizing coloring can be expressed as Y/H.Y.ZX, Y stands for drawing (the symbol for drawing means I haven’t found it yet), and / means there are two processes before and after.

[paging] The coloring methods are different:

One is to add pigments to the treatment liquid. The red and blue colors of the product are generally like this.

The second is to add some color developing agents, such as oxalic acid, etc.

The third is to add both of the above.

“Electrolytic coloring” is conductive oxidation. Generally, aluminum plates are conductively oxidized to golden yellow.

Wire drawing can be made into straight grain, random grain, thread, corrugated and spiral grain according to decoration needs.

Straight-grain drawing refers to the machining of straight lines on the surface of the aluminum plate by mechanical friction. It has the dual function of removing scratches on the surface of the aluminum plate and decorating the surface of the aluminum plate. There are two types of straight wire drawing: continuous wire and intermittent wire. Continuous thread patterns can be obtained by scouring pads or stainless steel brushes through continuous horizontal straight-line rubbing on the surface of the aluminum plate (such as manual grinding with existing equipment or using a planer to clamp a wire brush on the aluminum plate). By changing the wire diameter of the stainless steel brush, textures of different thicknesses can be obtained. Intermittent silk patterns are generally processed on brushing machines or rubbing machines. Production principle: Two sets of differential wheels rotating in the same direction are used. The upper set is a fast-rotating grinding roller, and the lower set is a slow-rotating rubber roller. The aluminum or aluminum alloy plate passes through the two sets of rollers and is brushed out. Delicate intermittent straight lines.

Chaotic wire drawing is a kind of irregular and non-obvious matte silk pattern obtained by moving and rubbing the aluminum plate back and forth under the high-speed copper wire brush. This kind of processing has higher requirements on the surface of aluminum or aluminum alloy plates.

The corrugation is generally made on a brushing machine or a rubbing machine. Use the axial movement of the upper group of grinding rollers to brush on the surface of the aluminum or aluminum alloy plate to obtain wave patterns.

Swirl is also called optical rotation. It is a kind of silk pattern obtained by using cylindrical felt or grind nylon wheel to install on a drilling machine, blending polishing oil with kerosene, and rotating and polishing the surface of aluminum or aluminum alloy plate. It is mostly used for decorative processing of round signs and small decorative dials.

The thread is to use a small motor with a round felt on the shaft, fix it on the table, at an angle of about 60 degrees with the edge of the table, and make a carriage with a fixed aluminum plate for pressing tea, on the carriage A polyester film with straight edges is used to limit thread competition. Using the rotation of the felt and the linear movement of the carriage, a thread pattern with the same width is rubbed on the surface of the aluminum plate.

Sandblasting is to obtain the surface of the light decoration or fine reflective surface to meet the special design needs such as soft gloss. Even and moderate sandblasting can basically overcome the common defects of aluminum surface.

For appearance parts, whether it is wire drawing or sandblasting, it usually needs surface oxidation treatment. As for which processing technology to choose, it should be an issue to be considered related to modeling. The surface textures obtained by the two processes are still different.

In addition, there is a process similar to sandblasting, but it is carried out by a chemical corrosion method, commonly known as chemical sand-blasting treatment or chemical sand surface corrosion. It is especially suitable for aluminum surface treatment. The uniformity of the sand surface is far better than that of blasting. Sand treatment. Chemical sand surface corrosion is divided into acid corrosion and alkaline corrosion. Different corrosive solvents and sand surface agents can obtain different surface colors and sand grain thicknesses.