Extrusion / Press 18 MN
Aluminum extrusion is a technique used to transform aluminum alloy into objects with a definitive cross-sectional profile for a wide range of uses. The extrusion process makes most of aluminum’s unique combination of physical characteristics.
Its malleability allows it to be easily machined and cast, and yet aluminum is one third the density and stiffness of steel so the resulting products offer strength and stability, particularly when alloyed with other metals.
The process of aluminum extrusion consists of the following steps:
- After designing and creating the shape of the die, a cylindrical billet of aluminum alloy is heated to 500°C
- The aluminum billet is then transferred to a loader, where a lubricant is added to prevent it from sticking to the extrusion machine, the ram or the handle.
- Substantial pressure is applied to a dummy block using a ram, which pushes the aluminum billet into the container, forcing it through the die.
- To avoid the formation of oxides, nitrogen in liquid or gaseous form is introduced and allowed to flow through the sections of the die. This creates an inert atmosphere and increases the life of the die.
- The extruded part passes onto a run-out table as an elongated piece that is now the same shape as the die opening. It is then pulled to the cooling table where fans cool the newly created aluminum extrusion.
- When the cooling is completed, the extruded aluminum is moved to a stretcher, for straightening and work hardening.
- The hardened extrusions are brought to the saw table and cut according to the required lengths.
- The final step is to treat the extrusions with heat in age ovens, which hardens the aluminum by speeding the aging process.
Among the many surface finishing options for aluminum extrusion products, powder coating is the most favored, durable, and cost-effective alternative. This method makes surfaces long-lasting and functional while also producing a decorative appearance.
The procedure covers the entire range of RAL colours. Special colours, different textures as well as different surface appearance effects, such as matt, shiny or metallic are possible as well. Powder-coated surfaces can be produced in a highly weatherproof quality. Whether for products used in the home or in commercial businesses, powder coating increases protection from cold, heat, corrosion, scratching or even bleaching under the hot sun.
Process of Powder Coating
Powder coating finishes on aluminum extrusion products involve a systematic process, which starts with the pre-process inspection to check for any surface anomalies or damages. The rest of the process is covered primarily in three steps as follows:
- Pre-Treatment: The most important part of the process, this defines the durability and longevity of the end product. It involves the removal of dust, grease, or any other foreign particles using chemical and mechanical methods. This ensures that the surface is clean for enhanced adhesion and to prevent flaking.
- Powder Application: The powder used in the process is the fine mixture of colored pigment and resin, which is commonly applied with an electrostatic spray gun.
- The powder is given a positive charge that causes it to bond to the electrically grounded surface of the product. Curing: The object is heated in an oven for a set duration at a fixed temperature, causing the powder to melt uniformly, thus forming a hard coating when cooled.
- Powder coating finishes offer a number of benefits in addition to their cost effectiveness. The wastes produced during the process can be recycled or disposed of in an environmentally friendly manner. Powder coating is an excellent alternative for creating a functional and beautiful finish for aluminum extrusion products.
The process of aluminum anodizing adds a layer of oxidation to aluminum extrusion products. Unlike iron or carbon steel where oxidation creates a layer of corrosion or rust, the anodizing process actually enhances the properties of aluminum. The hard, oxidized layer becomes a part of the aluminum, creating numerous beneficial properties.
Benefits of Aluminum Anodizing
Aluminum anodizing enhances the advantageous characteristics of aluminum in several ways:
- Durability: Since anodized aluminum extrusion products have a protective layer, they are more resistant to wear from normal handling and usage.
- Finishing: The process creates a more aesthetically pleasing finish, with either a clear or colourized appearance.
- Corrosion resistance: The thick outer coating produced, along with proper sealing, increases the corrosion resistivity of the surface as it prevents further oxidization.
- Lasting Color: The color finish added to anodized aluminum is more enduring due to the surface obtaining more adhesive and porous qualities during the anodizing process. The resulting anodic film coating allows for effective dyeing processes to be applied.
- Strength: The anodized aluminum surface is harder than pure aluminum, second only to diamonds with respect to its hard crystalline structure.
- This enduring treatment improves the strength and aesthetics of aluminum extrusion products for easy maintenance and long life in any conditions, whether it be indoors or out in the elements.
A variety of methods are used in aluminum extrusion mechanical processing to achieve accuracy in the finished components.
Selection of the elements of the mechanical process depends on the end use and specifications of the product being manufactured.This may be a simple procedure or a complex system that offers more precise specifications, the creation of prototypes or the production of a large quantity of parts.
Thermal break means a sudden reduction in temperature of transition from one object to another.
Today's thermal break material is normally made from a durable polyamide material. Profiles with a thermal break have the feature of high strength and bearing capacity, aesthetic design, but what distinguishes them from other profiles, the feature of thermal insulation.
Aluminum profiles consist of two parts that are interconnected by insulating material - polyamide tape of various dimensions (14.8 mm, 16 mm, 18 mm, 28.6 mm, 31.6 mm).
Polyamide is a plastic that insulates more than 500 times better than aluminum, so thermal break profiles have a much lower Uf value. Thermally broken profiles in combination with appropriate filling (glass, panel, etc.) are used in the occasion where high thermal insulation requirements have to be met. Polyamide prevents the passage of heat from the inner part of the aluminum profile to the outer part and vice versa.
Profiles with a thermal bridge are used for those elements and typologies, which must meet the thermal insulation and are used for residential and business premises. Additional benefits of thermally broken aluminium windows and doors:
- Conducts heat and noise 1000 times slower than normal aluminium
- Flame retardant
- Added layer of security
- Low maintenance
- Long lasting
- Thermal break technology
- Excellent thermal and acoustic insulation
- Powder coated surfaces with a large range of colors