Powder coating of aluminum profiles

Powder coating of aluminum profiles

The latest requirements of our time have burst into our life at a rapid pace — light, airy structures made of glass and concrete, high-rise facades made of aluminum and glass of a certain color, shade, aesthetic and reliable aluminum windows and doors, winter gardens that retain heat, radiate comfort and a flow of positive energy. High quality indicators of these structures are ensured by modern glass processing technologies and an effective colored coating of aluminum building.

Powder coating of an aluminum profile for building structures is an effective color coating with a long-term preservation of the original color of the coating and its gloss.

In order to obtain a good powder coating on the aluminum surface, this surface is subjected to a complex chemical preparation technology.

The purpose of chemical surface preparation for powder coating:

  • Removing all contaminants from the surface, including dirt, oxides, greases and oils.
  • Creation of a surface for optimal powder coating adhesion.
  • Achieving maximum uniformity over the entire surface of the painted product.

Stages of preparing the surface of aluminum for powder painting:

  • Degreasing in special detergent solutions.
  • Thorough rinsing in clean water after all chemical work steps.
  • Etching in a chemical solution for a specified time and at a specified temperature.
  • Final rinse in deionized water.
  • Removal of residual moisture — drying in a convection oven with intensive hot air.

Only the complete fulfillment of all requirements for the preparation of the aluminum surface makes it possible to realize the full potential of powder paint to create a strong and durable protective and decorative coating.

Surface prepared aluminum products are supplied to the powder coating line. The first stage of this process is the application of powder to the surface of the product — an aluminum profile. The aluminum profile enters an electrostatic spraying chamber in which electrically charged particles «stick» to the profile surface.

The electric charge of a powder particle is obtained when passing through special pistols. All powder, which did not have time or could not «stick» to the profile, enters the powder recirculation system and returns for reuse. This is the principle of electrostatic powder coating.

The sprayer combines a number of different operating modes:

  • stress can spread both up and down;
  • powder output speed (paint flow force) can be adjusted;
  • the distance from the nozzle outlet to the workpiece may vary.

After applying the powder paint, the product goes through a coating formation stage. It involves melting the paint layer, then making the coating film, curing it and cooling it down. The reflow process takes place in a special reflow and polymerization oven. Powder coated aluminum profiles pass through the technological chain into an oven, which is called a polymerization oven. In this oven the profiles are kept for 15-20 minutes at a temperature of 160 to 210 ºС, depending on the type of powder paint. When heated, the powder particles melt and form a continuous, uniform coating. In this case, the polymer compounds that make up the powder undergo polymerization with the formation of new chemical bonds.

The coating thickness at the outlet is 50-60 microns. The main requirement for polymerization chambers is to maintain a constant set temperature (in different parts of the furnace, a temperature spread of at least 5 ° C is allowed) for uniform heating of the product.

After leaving the oven, the profiles are allowed to cool down to room temperature for inspection, packaging and shipping. After painting in this way, the strength characteristics of the product do not change even at high temperature fluctuations. Thanks to this technology, you will not have to update the product for almost the entire operational life.

Thermoset powder paints are available in a wide range of colors. For powder coating of aluminum profiles, the international RAL color scale is used.

RAL is an organization in Germany that standardizes and certifies colors for paints and coatings. In addition to the color according to the RAL scale, the degree of gloss of the coating is usually also specified — matt, semi-matt, glossy (glossy).

degree of gloss of the coating
semi-matt degree of gloss of the coating
degree of gloss of the coating

Matt finishes are especially popular for powder coating aluminum profile building products such as windows and doors.

Semi-matte — for facade elements, as they are less noticeable processes of chalking and fine-crystalline cracking under the influence of ultraviolet radiation, dust, precipitation.

Glossy coatings are applied to elements of furniture, sports equipment, playgrounds, flower stands, sliding systems, billboards, when decorating stained glass windows, etc.

Powder coating allows you to get a perfectly smooth and even coating, to ensure the reliability and durability of the coating both indoors and under the influence of environmental factors — coloring pigments penetrate into the pores of the heated metal and are combined with the top layer of the aluminum profile. After cooling, the paint does not crack, peel off and does not change color and gloss for decades. Painted facades, windows, doors serve you for a long time, delight the eye and make your space stand out among standard gray reinforced concrete buildings.