Bright etching is a cutting-edge technology for the surface treatment of aluminum alloys. After a deep transformation of the acid etching bath, it is equipped with a sand-surface polishing tank and a smooth-light polishing tank to perform bright processing on the acid etching material.
Technical brief
Bright acid etching is a cutting-edge technology for surface treatment of aluminum alloys. After a deep transformation of the acid etching bath, it is equipped with a sand-surface polishing bath and a smooth-light polishing bath to perform bright treatment on the acid-etched material. This not only preserves the etching mechanism. The advantages of strong grain ability, quick sand production, low aluminum consumption, and the ability to completely remove acid ash, solve the drawbacks of the darkening of the surface of the acid etching material and the contamination of the coloring tank and the electrophoresis tank are a rare technological breakthrough. The technology is at the forefront of international processing. And declared two national invention patents.
Bright etching completely solves the world problem of darkening of acid-repellent sand face materials. It is the upgrading technology of existing aluminum surface pretreatments such as common alkali etching, common acid etching, and low-temperature polishing; it can not only produce flat light materials and sand blasting Material, but also the production of a new bright acid etching matte. The technology has been put into use in many large-scale aluminum processing companies such as the Guangdong Xingfa Group. The large-scale application of this technology will have a wide and far-reaching impact on China's aluminum processing companies.
Since 2000, aluminum alloy acid etching technology has many advantages such as strong mechanical texture, fast sand development, and low aluminum consumption. In less than one year, it has rapidly replaced alkali etching and become the pretreatment of aluminum alloy oxidation. Mainstream production process. However, since the date of the promotion of the technology, the problem of the darkening of the surface of the aluminum alloy has been plagued by the manufacturer and has also affected the product quality. In order to overcome the above defects, most manufacturers are equipped with alkaline pitting and neutralization tanks. Even so, the acid etching material is still much darker than the alkali etching material and does not solve the problem fundamentally. In addition, the acid-etched ash on the surface of the aluminum alloy is very stubborn, and even after alkali etching, light-emitting tanks, and oxidation tanks are not completely removed, they are still brought into the coloring tank and the electrophoresis tank, causing the coloring material to hang dust, Electrostriction shrinkage, many aluminum alloy factory had to re-use alkaline tanks. Bright etching is a cutting-edge technology for surface treatment of aluminum alloys. After a deep transformation of the acid etching bath, it is equipped with a sand-surface polishing bath and a smooth light polishing bath to perform bright processing on the acid-etched material, not only retaining the etching mechanism. The advantages of strong grain ability, quick sand production, low aluminum consumption, and the ability to completely remove acid ash, solve the drawbacks of the darkening of the surface of the acid etching material and the contamination of the coloring tank and the electrophoresis tank are a rare technological breakthrough. At the same time, mechanical sandblasting materials also have the problem of surface ashing and darkening, and also need to be brightened. The sand surface material treated by bright etching technology has no grain, no ash, fine sand, and beautiful surface. In addition, bright acid etching technology for degreasing, film removal, brightening and ash removal, can replace the low-temperature polishing tank, and three-in-one tank, production of flat light. It can be predicted that with the rapid popularization of bright acid etching technology, the international competitiveness of China's sand surface aluminum alloy is expected to increase rapidly.
Technical features
Bright etching technology consists of four processes: deoiling, brightening and etching, sand surface polishing and smooth light polishing. The deoiling and dewaxing tank is responsible for degreasing, dewaxing and natural oxide film. Brightening and etching grooves are responsible for the pattern removal. , sanding and adjusting the background color of the aluminum alloy until the initial blue and shiny; sand surface polishing tank is responsible for removing acid ash and sand surface material for low temperature polishing; flat polishing tank is responsible for further increase brightness and precision ash, and fixed aluminum Alloy metallic luster. The four processes are interdependent and cooperate with each other to form a complete and strict bright acid etching technology. The core of this technology is the low-temperature polishing of polished materials and the low-temperature polishing of light materials. That is, the combination of deoiling dewaxing tank, brightening acid etching tank, sand surface polishing tank and flat polishing tank can produce bright and etched matte materials; the combination of sand surface polishing tank and flat polishing tank can produce bright etching sandblasting material; The combination of deoiling and dewaxing tanks and flat polished grooves can produce bright and etched flat light. The use of this set of technology allows the alkali tank to completely withdraw from the production process (reserved only for film stripping) and greatly reduce the aluminum consumption. This technology, combined with post-processing techniques such as coloring and electrophoresis, can produce the brightest bright acid-etched (coloring, electrophoretic) aluminum alloys ever produced.
The characteristics of this set of technology are as follows:
1. The concept of brightening and etching is proposed for the first time. At the same time when the aluminum alloy is stripping and sanding, the background color is green and shiny. Ordinary etching groove, its function is limited to sanding and graining, the background color of aluminum alloy is grayish white, very ugly. The company's R&D department fully paid attention to this issue, and made profound transformations to the acid etching bath. The brightening acid etchant was successfully developed so that the aluminum alloy was etched and the background color was green and bright!
2. For the first time, a complete set of four-slot combination technology is proposed, and the aluminum alloy is completely treated with an acidic method, covering all oxidation pre-treatment processes under low temperature conditions. Although conventional alkali etching methods can also produce matte materials, plain materials, and sandblasting materials, excessively high aluminum consumption, insufficient brightness, and coarse grains of sand make them gradually replaced; ordinary acid etching cannot produce flat materials, but general low-temperature polishing Can not produce matte materials. This set of technology consists of degreasing dewaxing tank, brightening acid etching tank, sand surface polishing tank and flat polishing tank, which can produce bright and etched matte materials. The degreasing and dewaxing tank and flat polishing tank combination can produce bright Acid etching flat light material; sand surface polishing tank and flat light polishing groove combination, can produce bright acid etching sandblasting material. Since these aluminum alloys are produced under acidic conditions and undergo a polishing process, they all have the characteristics of low aluminum consumption and high brightness.
3. For the first time, the concept of flat light polishing was proposed. The brightness of the polished aluminum alloy was first fixed, and the loss of light from the anodization was effectively reduced. Anodic oxidation results in loss of polishing of the polishing material, which is a consensus of the aluminum processing industry. In general, the anodizing tank itself is seeking ways to reduce the loss of light, and it is difficult to have a major technological breakthrough. For the first time, the R&D team looked for ways to solve the problem of loss of light outside the anodizing tank. That is, by using the technology of fixing in the phase washer, it tries to fix the polishing brightness of the aluminum alloy first, and then anodizes it, effectively reducing brightness loss. After nearly three years of painstaking research, we finally found a clever way to solve the problem. That is, a flat polished groove is provided between the sand-surface polishing tank and the anodizing tank to chemically oxidize the polishing material without losing the light (but increasing the brightness). A very dense chemical oxide film is formed on the surface of the aluminum alloy, the brightness is first fixed, and then the anodization is performed to effectively reduce the loss of light; for many industrial materials and interior materials, only the organic sealing can be performed. Factory
4. The concept of sand surface polishing was put forward for the first time, and ash removal and polishing were performed in a tank, which achieved a major technological breakthrough in the complete removal of acid etching ash. At the same time, it also obtained the low-temperature polishing effect of sand surface materials. Since the advent of etched sand surface technology, how to remove acid ash is a very difficult problem for the aluminum processing industry. Although many solutions have been proposed, none of them can fundamentally solve the problem, and alkali tanks and neutralization tanks have to be extended, which not only increases the aluminum consumption, but also does not completely solve the problem of acid etching. The application of the sand surface polishing agent enables most of the acid etching ash to be removed, the aluminum alloy restores the metallic color, and obtains a considerable degree of polishing effect.
Technical process
1 Deoiling and dewaxing -> 2 washing -> 3 brightening etching -> 4 sand surface polishing -> 4A washing -> 4b washing -> 5 flat polishing -> 5A washing -> 5B Washing--> 6 Washing-->7 Oxidation
1. Deoiling dewaxing tank: This degreasing tank is different from the general AC degrease, in addition to degreasing, dewaxing function, but also off the natural oxide film, to the surface of the hair, and low-temperature polishing; deoiling dewaxing tank The combination of sand polishing and smooth polishing grooves can realize the most powerful cryogenic polishing function so far, and produce bright and etched flat light materials.
2. Brightening Etching Groove: This slot is made by adding special additives on the basis of the existing etching pits. It keeps the original slag slag device unchanged, without additional heating and cooling. Brightening acid etching is essentially different from ordinary etching. First, the ability of ordinary etching to remove mechanical textures and surface flaws is weak. After light treatment, surface defects are exposed. Brightening acid etching greatly improves the ability of acid etching grooves to completely eliminate surface defects in the same or shorter time. Secondly, the surface of aluminum alloy after ordinary etching treatment is very dark, and ash removal and brightening are required. It is very difficult to increase the pressure of the sand surface polishing tank and the flat polished groove. In addition to prolonging the polishing time, the consumption of sand surface polishing agents and flat light polishing agents is also increased. Brightening acid etching can improve the ability of etching, at the same time, it can make the background color of aluminum alloy blue and bright, and lay a good foundation for the subsequent sand polishing and peace polishing process.
3, sand surface polishing tank: sand surface polishing is a new surface treatment concept, is a profound transformation and transformation of acid etching technology. After the aluminum alloy is etched, it is not an over-alkali tank but a sand-surface polishing tank. The ash removal and polishing are performed on the acid etching material, which not only retains the fine sand of the acid etching material, but also has no grain and low aluminum consumption, and increases the light. The combination of brightness and metallic color, brightening acid etching and sand surface polishing technology, can produce a new type of material - bright, acid-etched matte material with no grain, fine sand, bright and retained metallic color. In addition, the sand surface polishing tank can brighten the blasting material, improve the grade of the blasting material, and produce bright etching sandblasting material. The sand surface polishing tank is grooved in the ordinary antiseptic tank, no heating, no cooling, no slagging, a small amount of acid slag is crystallized at the bottom of the tank, and the tank is cleaned at the end of the year.
4, flat polishing tank: set the tank has two major purposes, namely the polished surface of the aluminum alloy flat polished and refined ash.
A, flat polishing: flat polishing tank can not only generate a certain thickness of oxide film, but also significantly increase the brightness of aluminum alloy. As the anodization degrades the aluminum alloy after the sand surface polishing treatment, it is first polished with a flat surface, a dense oxide layer is formed on the surface, the gloss is fixed, and then the anodization is performed to substantially reduce the loss of light; Before the alloy is polished from sand surface to anodized, it needs to be washed in multiple ways, and may be trapped in the air or in the washing tank, resulting in pitting corrosion. If the polishing tank is first polished, a certain thickness of chemical oxide film is pre-prepared to protect it, so as to avoid Before the oxidation, pitting or flowering material is generated in the washing tank to increase the yield.
B. Fine ash removal: Acid etching ash is very stubborn and difficult to remove by ordinary methods, which can seriously affect the appearance quality of acid etching materials. Although the sand surface polishing tank can remove most of the acid ash, there may still be a small amount of residue under certain special conditions. The flat polishing tank can completely remove the acid ash, thus ensuring the quality of the aluminum alloy, and completely eliminate the pollution of the coloring tank and the electrophoresis tank by the acid etching ash.
5. Operation method: Aluminum alloy is deoiled after 1-4 minutes, then it is washed with water and then it is brightened and etched. After 4-12 minutes of reaction, it is not washed with water, and it is directly put into sand polishing tank. Reaction is 3-9 minutes. After washing, into the flat polishing tank, after 3-7 minutes of reaction, after two rinses, the anodic oxidation tank can be introduced to complete the surface pretreatment.
Bright acid etching research background
The bright acid etching technology of aluminum alloy is the foundation of the developed leveling and brightening technology and chemical polishing technology. It has also developed another exclusive proprietary technology. In recent years, relevant technicians have conducted detailed studies on the various processes of aluminum anodizing pretreatment, such as alkaline etching, acid etching and triacid polishing, and found that:
1, aluminum alloy brightness: triacid polishing solution, due to the presence of strong oxidizing agents such as nitric acid, so that the aluminum alloy surface is easily oxidized out of a passivation layer containing dense alumina, thus forming a mirror, so the most polished tri-acid Bright; alkaline etching without passivation, no polishing effect, but it can retain the metal color; acid etching is the darkest, aluminum alloy surface covered with a layer of acid ash, no metal luster.
2. Mechanical pattern: In the etching solution, the reaction product adheres to the surface of the aluminum alloy and fills the bottom of the mechanical groove. The aluminum alloy of the groove is completely isolated from the acid etching solution. The reaction rate is almost zero, and the surface of the groove is adhered. The product is thinner and the etching solution can be in contact with the aluminum alloy, and the reaction can proceed quickly.
3, sand surface: acid etching and alkaline corrosion formation of the surface of the sand is different, resulting in different sand.
4.Comprehensive cost comparison: The cost of tri-acid polishing is the highest.
5, the appearance of quality comparison: In terms of brightness, the brightest tri-acid polishing, alkali etching followed, the darkest etching; from the sand surface, the etching sand is uniform and delicate, alkali corrosion sand coarse uneven; three acid polishing basic Can not afford sand; Similarly, the ability of acid etching to mechanical patterns is more than three times that of alkaline etching, and tri-acid polishing has no ability to remove lines.
Based on the above-mentioned profound understanding of pre-oxidation treatment, related R&D personnel have identified three major research topics:
Aã€<<Aluminum alloy bright etching technology>>: This technology is a profound transformation of the acid etching technology, both require the preservation of uniform and delicate sand surface erosion, efficient and thorough mechanical texture, and must completely remove acid etching Gray, restores metal color, and has a certain degree of polishing ability. Through nearly three years of scientific and technological research, the above technical indicators have been achieved.
Bã€<<Aluminum alloy leveling and bright technology>>
Cã€<<Aluminum alloy acid low temperature semi-polishing technology>>
Brightening acid
The product function is a kind of special effect, strong acid etchant. It is a profound improvement to common acid etchant and other buffers such as ammonium dihydrogen phosphate. It is an additive that can improve the ability to remove mechanical patterns and increase the brightness, and contains aluminum alloy Erosion, the active component of the bath buffer pH value, its characteristics are as follows:
1. Add directly in the original etching tank, do not change the equipment, do not open a new tank;
2, to improve the ability to remove grain, sand more delicate;
3, improve the profile brightness, the beginning of the metal color;
4, strong buffer PH, do not adjust the bath.
Bath solution management
Grooving: acid etching slotting agent 200 kg / m;
Ammonium fluoride 100 kg/m.
Working temperature: 35-45°C.
Working hours: 3-12 minutes.
Add: Etching additive 10Kg/ton material; Ammonium hydrogen fluoride 40Kg/ton material.
Test indicators: fluoride ion concentration 45-60g/l.
PH value of 3.0-3.5 (test paper).
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