SUBCONTRACTED SURFACE TREATMENT
In terms of its size, FinEq has the most modern surface treatment facility in Eastern Finland, equipped with nanoceramic pretreatment and an automated production line. The unique, 210-meter production line system of the industrial powder coating plant enables the treatment of even large volumes ecologically, efficiently, and economically. Due to its efficient pretreatment and powder coating processes, the line provides a marine grade outcome with a single coating. In addition, the large powder coating oven can easily treat large products and even pieces up to 12 meters long separately. The main clients of the surface treatment production are companies operating in the metal industry in the Savo and Karelia region.
Powder coating is the most common painting and lacquering method for metals and metal products. It gives products and raw materials an extremely hard surface that has high mechanical and chemical wear resistance. Powder coating has significant benefits especially in terms of high-volume sheet metal products: it is an affordable, fast, and durable coating technique and perfectly suitable also for multidimensional pieces and cast products. The products’ color tone and degree of shine can be selected from an extensive range of options.
Powder coatings are environmentally friendly. Unlike liquid paints that require a solvent, powder coating does not emit volatile organic compounds (VOCs) into the environment. Moreover, the powder can be recycled and reused, which makes powder coating even more economical. Powder coating is the right choice when you desire a high-standard, quality product.
Our powder coating plant has the capacity to treat products up to environmental stress category C5 High. Powder coating is used in e.g. the aluminum profile, metal furniture, and machine industry, as well as in the heating, ventilation, domestic appliance, and automobile industry.
THE POWDER PAINTING PROCESS
Pretreatment of products and materials to be coated is at least as important for a successful outcome as the coating process itself. Pretreatment and its quality influence several factors, such as the visual quality of the paintwork, the durability of the paintwork (lifecycle), the adhesion of the coating, and many other properties required of the paintwork in different environments.
- After receiving the product, its need for pretreatment is assessed. After this, the parts of the product that should not be coated are protected with silicone plugs or tape. Prior to the actual production process, holes for suspending are made in small products, max. 1000 x 1600 x 3860 mm, and they are hung on the line on metal hooks. Larger pieces, max. 1000 x 2000 x 14000 mm, are coated separately using a trolley.
- Products to be coated go through a five-step pretreatment process before powder coating begins. First, they are given an alkaline oil removal wash and demineralized rinses. Next, a nanoceramic coating is applied to the surface of the product, which protects from corrosion and provides an excellent adhesive surface for powder coating. This pretreatment is environmentally f riendly, because no chromium or phosphate is used.
- Following the pretreatment process, the pieces to be coated are left to dry in the drying oven befor applying the powder coating. The pieces are not powder coated until they are entirely dry and cooled.
- The powder contains a fine color pigment and a resinous binder. Powder coating is done either in a special, automatic coating booth or manually using spray guns. The powder is electrically charged in the spray guns and sprayed onto the products. When using the powder coating technique, compressed air makes the powder hover loosely in the container so that it can be sprayed. When the product itself has been grounded, the powder particles gravitate toward the surface and form an even layer. Powder that has missed the product is recovered so that the powder coating plant can reuse it. Depending on the required standard, a durable surface between 30–500 µm is achieved.
- After powder coating has been applied, the pieces are moved to a gas-heated oven (200°C) where the surface undergoes crosslinking and achieves the right color and texture. In other words, the coating is cured or polymerized in a cure oven. The color pigment particles and the resinous binder melt and harden in the oven, forming an even, resistant, and elastic surface.
- The curing time depends on the size and thickness of the piece. The curing time of coated products depends on the thickest part of the piece. After curing, the pieces are cooled down and are ready for finishing.
- The powder coating plant also handles product packaging and finishing. Once the finished products have cooled, they are removed from the coating line, the quality of the coated surface is checked, and the products are packaged according to the customer’s instructions. Assembly tasks may also be carried out, if necessary.
Various kinds of powders are available, depending on the piece or the quality of the surface. Epoxy, polyester, and acrylic powders are the most common types of powders. Metal, lacquer, and sheet metal powders are also used in special sites.
Epoxy and polyester-epoxy are ideal for products used indoors and/or if the coating needs to be highly resistant to solvents or other chemicals. They also have the hardest surface, hence the highest mechanical wear resistance.
Polyester is excellent for products used outdoors, because it is highly weather- and UV-resistant. Polyester powder is also relatively elastic as far as powder coating goes, so it is suitable for products that are expected to encounter stress from collisions or battering. The best level of adhesion is achieved only through proper pretreatment, regardless of the powder type.
Polyurethane: Same as above, also for indoor use when a particularly smooth and shiny surface quality is required.
Silicone: Heat-resistant powder that works similarly to traditional heat-resistant paints, i.e. tolerates use in high temperatures (400–650 degrees).
We use the powder coatings of e.g. the Finnish company Teknos.