How to improve aluminum alloy dyeing color uniform

First of all, let's take a look at what are the reasons for the dyeing un-uniform of aluminum alloy after oxidation:

1. 1. The alkali washing before the workpiece is not thorough enough.
2. Dyeing melt temperature is too low.
3. There is oil stain on the surface of the dyeing solution.
4. Rework products with uncleaned film layer.
5. Oxide film is polluted.
6. The water washing after oxidation is not thorough enough and is not cleaned.
7. The current density is too large when the aluminum profile is anodized.
8. The temperature of anodic oxidation solution is too low and the current density is too small.
9. The anodic oxidation solution temperature of aluminum profile is too high.

From the above reasons, most are because of production operations, such as: temperature, current or aluminum unqualified, can be controlled, as long as the operator pay a little attention to it. But some factors are hard to control.

Aluminum alloy surface dyeing may be not thoroughly washed after oxidation. So why not clean? In fact, it is the residual acid in the cracks and blind holes of the workpiece. We know that the anodic oxidation is to generate a layer of dense multi-pore oxidation film, and the dyeing after oxidation is also achieved by using the porous layer of the film to adsorb the dyeing material. In the process of anodizing, the porous layer will also enter the oxidation solution such as sulfuric acid. Therefore, there is the process of washing after oxidation. However, the holes in the porous layer of the oxide film on the surface of aluminum alloy are very small and difficult to distinguish with the naked eye, so this adds a lot of difficulty to cleaning. It is impossible to control the degree and time of washing, so it is often washed unclean, resulting in subsequent dyeing and flowering. In cases like this, there is also a targeted approach, that is, the use of special adjustment solvent for acid removal. This is also the most widely used method on the market. It has the advantage of not affecting the film, but also can open the oxide film thoroughly, so that the dye is uniform.