Anodized aluminum, electrophoretic washing technology

In surface treatment plants such as anodization of aluminum (including electrophoresis), various (electrical) chemical reactions are performed in (electro)chemical reaction tanks, and the water wash process is not very complicated in principle, so field management is often very careful. The management and maintenance of the reaction tank neglected the importance of washing. Experience has shown that the maintenance and management of (electro)chemical reaction fluids is very important in the process management of surface treatment plants. However, inadequate water washing process is also a major cause of poor surface treatment quality and difficulty in stable production of surface treatment lines. In fact, the washing process plays a decisive role.

The washing process of a typical surface treatment plant mainly has the following positive aspects:

The first is to prevent cross-contamination of the reaction solution. When the processing of the workpiece is completed before entering the next step, the water washing operation is performed so as not to bring the medicine of the previous process to the next process and influence the composition of the next process (in contrast, the components of the current process do not affect the next process. The process can be simplified or omitted from the washing process).

The second is the product's own quality requirements. When the treatment solution remains on the surface of the product, which will affect the product performance and the value of the product, it must be washed.

Third, the quality of washing technology also affects the consumption of surface treatment drugs. If the acidic degreased solution of the aluminum pre-treatment is not washed, it will enter the alkali etching tank, and then it will enter the neutralization tank after insufficient washing, so that repeated times will eventually lead to a decrease in the effective concentration of each tank and generate a large amount of suspended solids at the same time. Or sediments, leading to increased consumption of drugs, treatment effects decline.

In addition, water conservation can be achieved. Surface treatment workshops, such as traditional aluminum anodizing, usually require the use of a large amount of water, which wastes water, increases the loss of metal salts, and pollutes the environment. Therefore, how to improve the washing efficiency? To improve the washing effect is an important topic for surface treatment.

Washed water type

According to different sources of water in China and the quality of water itself, water washing water is mainly divided into the following categories:

(1) Well water and river water The water that is drawn directly from the river or well is not the same, and the type and concentration of impurities are not the same. Therefore, before using this type of water, water quality should be scientifically evaluated by measuring pH and conductivity of the solution.

(2) City residents who use tap water to sterilize the tap water. Contains more chloride ions, in addition, other components are analyzed and managed by the water company and have a certain concentration range. For the surface treatment shop cleaning its composition should be investigated.

(3) China Water is also called industrial water. It is used for urban greening and the use inside the factory. The water quality of different types of factories discharged is different, and some even contain large amounts of organic substances.

(4) Pure water Infiltrate the insoluble material in the raw water and then ion exchange the ion exchange resin. There is also pure water obtained through reverse osmosis treatment. The resistivity of pure water is 1.0×10 6 Ω·cm or more. In addition, distilled water is also used for pure water.

(5) The ultrapure water is treated with reverse osmosis membranes and ion exchange, and finally treated with a cleaner ion exchange system to obtain water free from impurities. Ultra-pure water can also be obtained by multi-stage distillation, but the amount of water is very limited. Resistivity varies depending on the application, and generally requires 1.2×107Ω·cm or more. The theoretical resistivity of pure water is 2.5×10 7 Ω·cm.

Because the requirements of different surface treatment workshops are different, and the amount of water consumption is not the same, in actual work, water of different quality is selected according to the specific conditions of the surface treatment workshop. Of course, in the same workshop according to the specific situation of the cleaning tank can also choose to use different water quality with the use of, such as the construction of aluminum oxidation workshop due to its large amount of water, if all the use of pure water, will need huge pure water treatment equipment, and construction of aluminum The surface treatment of the profiles is not very precise, so the pre-treated type of washed water can be directly used with tap water. Of course, the precision aluminum components (such as the printer's cartridge blasting aluminum tube) surface treatment workshops and electrophoresis workshops are very harsh on the processing environment, in this case, of course, use pure water or even ultra-pure water, and sometimes even need to use constant temperature water wash And clean room environment and other conditions.

Washing method

Basic washing methods are the following.

(1) Impregnating water washing is abbreviated as dipping, and the process of diluting the concentration of the liquid attached to the article is performed by putting the articles to be washed into an aqueous aluminum anodizing and electrophoretic washing technique. The desired degree of cleanliness is the diluted concentration of the contaminants brought into the wash tank. After washing the medicine on the item, it will not exceed the diluted concentration of the washing water solution. In the actual washing process, how to achieve the ideal dilution concentration and how to ensure the uniform concentration of the washing water is how to improve the washing effect and efficiency.

(2) Spray Washing is basically a water wash. Because it is spray washing, it can wash the liquid on the object while washing, and it can also dilute the liquid on the product. If the amount of water sprayed by the shower is large, and the speed of the water flow on the surface of the article is high, the rate at which the attached liquid is washed away is high. If the article can be fully spray-washed, a small amount of water can be used to obtain a better cleaning effect compared to immersion cleaning.

(3) Spray washing This washing method can also be considered as a type of spray washing. The spray cleaning of the mist-like water achieves the cleaning of the articles with a small amount of water. Compared with the showering effect, the washing effect is very obvious due to the dilution effect.