Production of Mirror Polished Aluminium Profiles

Mirror-polished aluminium profile is widely used in kinds of high-end civilian products, such as interior bathroom doors for home and hotel, and furniture products. The products made with mirror polished surface are luxurious in appearance and can be colored or dyed according to requirements. Mirror-polished aluminium profile has great difficulty in production due to its serious surface quality. Especially in the long-term 6M mass production process, how to achieve quality stability and reduce waste is even more difficult in production. The strict management of each production process can achieve a mirror-polished aluminium with stable quality. Below you can know the production process of mirror polished aluminium profile.

mirror polished aluminium profile-fonnov

Mirror Polished Aluminium Profile │ Ingot

The purity of the extruded aluminium ingot, the chemical composition has a great influence on the surface quality and polishing gloss of the extruded aluminum profile, so the high quality aluminium ingot is the prerequisite for polishing the aluminum. The higher the purity of the ingot, the better the polishing effect of the extruded aluminum profile. The purity of the aluminium ingot depends on the content of metal impurities and non-metallic impurities in the aluminium ingot. The metal impurities mainly refer to Fe, Mn, Cu, Zn, Cr, Ti, etc. The most important of these impurities is Fe. The content of Fe is preferably controlled to be 0.1% or less. On the other hand, non-metallic impurities also have an important influence. In addition to the selection of high-quality high-purity aluminum ingot, try not to add crushing scraps, especially anodized aluminium scraps.

Mirror Polished Aluminium Profile │ Extrusion Process

High-quality aluminium extrusion dies can improve the quality of subsequent aluminum surface polishing.

Choosing a suitable extrusion ratio. Too large or too small will affect the quality of the polished aluminum. For different types and extrusion ratio aluminum profile, it is the key to ensure the uniform quality of aluminum polishing by achieving the same control extrusion temperature. In addition, the protection of the surface of the mill finish extruded aluminium profile is also an important part of ensuring the quality of the polishing.

Mirror Polished Aluminium Profile │ Mechanical Polishing

mechanical polishing-fonnov aluminium

In order to achieve a good mirror effect, mechanical polishing is an extremely important part, especially for the 6M long aluminium profile. With a large polishing machine, this process serves the purpose of grinding and removing mechanical grain, and also enables the surface to be polished.

Mirror Polished Aluminium Profile │ Chemical Polishing

Mechanical polishing can give a good mirror effect, but aluminum is extremely oxidizable, so chemical polishing and anodizing processes are also required and necessary.

A common chemical polishing method is tri-acid polishing. Tri-acid polishing is the most important process in the production of polished aluminium profile. In order to obtain a stable, high-brightness and low-defect surface, the polishing process must be strictly controlled.

HPO4 is the main content of the chemical polishing. The mirror effect of the aluminum surface is formed by the viscosity effect. The higher the content, the more obvious the mirror effect, so the HPO4 content is the key factor to maintain the polishing brightness. HNO3 is the main component directly involved in the reaction, and its content must be strictly controlled. The concentration is too high, not only will produce a lot of yellow smoke, but also the reaction is too intense, difficult to control, and easy to produce over-abrasive, sanding and dry marks and other defects. If the concentration is too low, the optimum brightness will not be achieved. The specific gravity and temperature setting of the bath are also an important factor in ensuring the quality of the polished aluminum. The higher the specific gravity, the higher the temperature and the better the brightness of the polished aluminum. However, if the specific gravity is too high, the temperature will be too high and it will cause defects on the surface of the aluminum.

The anodizing process is the most serious process of matting in the production of chemical polishing products. The product is to ensure the surface brightness by using a low film thickness (≤5um), and the strict control of the anodizing process can minimize the extinction degree of the oxide film.

There are still many limitations to be solved in the production process of mirror-polished aluminium profile. There are mainly the following aspects:

  • The environmental protection treatment cost is too high, and the waste water and waste gas generated in the triacid polishing are very serious to the environment. The NO2 produced in the tri-acid polishing and various types of acid mist pose a potential hazard to the operator’s body.
  • Mirror polishing products have strict requirements on ingot casting, extrusion, mechanical polishing, chemical polishing and anodizingprocesses due to their surface requirements, which make the price of mirror polishing products high.
  • Product use is limited. Since the anodizing film thickness of the mirror polishing product is higher than 6um, the polished surface is matte severely in brightness, so the thick film polished aluminium profile can not be produced, so the mirror polishing aluminium profile is generally only suitable for indoor products.

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By | 2019-09-25T04:00:59+00:00 September 25th, 2019|Aluminium Extrusion|0 Comments