What Are Aluminum Extrusions?
What are aluminum extrusions? They are solid, semi-hollow and hollow shapes made from aluminum and used in the construction of everything from home appliances to spacecraft. Sapa Extrusion is North America’s leader in common alloy standard and custom aluminum extrusions. Our nationwide network of production and supply facilities enables us to produce all shapes, sizes, alloys and tempers suitable for any type of application.
The process of extruding aluminum begins with a solid, cylindrical block, or billet of metal. It is heated until softened and then forced through a steel die to produce lightweight, strong and corrosion-resistant components that are shaped like the opening of the die.
The two conventional methods of extruding aluminum are:
Direct extrusion - This is the most common method. The billet is placed in a stationary container while a hydraulic ram moves through to push it through the die opening. The aluminum flows in the same direction as the ram travels.
Indirect extrusion – In this method, the die stays in place while the aluminum billet and the container move in unison. The pressure of the ram forces the soft metal to flow through the die opening in the opposite direction of the ram. This is also called backwards extrusion.
The extrusion process can be continuous, to produce long components, or semi-continuous, to produce many pieces, and the parts can range in size from one millimeter to several feet long. Extrusions can be fabricated in complex shapes because of aluminum’s light weight and malleability, such as hollow and multi-chamber profiles that would never be possible with other metals.
Think of extrusion like squeezing toothpaste from a tube. The continuous stream of toothpaste will take the shape of the round tip, just as an aluminum extrusion will take the shape of the die. If you flatten the tip of a toothpaste tube, a flat ribbon of toothpaste will come out. If you change the tip, you can produce an entirely different shape. With the aid of powerful hydraulic presses that can exert 100 to 15,000 tons of pressure, aluminum can be extruded into just about any conceivable shape.
During extrusion, maintaining temperature control is a crucial element of the process. The temperature of the container must remain constant at all times during the cycle, top to bottom and front to back. Temperature is limited by the alloy being used and by the shape being extruded. For example, lower extrusion temperatures will usually produce shapes with better quality surfaces and more accurate dimensions, while excessive temperatures may decrease the tensile strength.
Aluminum’s ability to conduct heat makes it ideal for use as heat shielding or heat transfer components. The surface of the extruded parts can be finished in many different ways, such as anodizing, painting and powder-coating. Each process creates a coating with unique characteristics that can be used in a myriad of commercial, industrial and consumer applications.
With extrusion presses throughout the U.S. and Canada, Sapa has the capacity to supply all shapes, sizes, alloys and tempers utilizing both direct and indirect extrusion methods. From standard and custom extrusions that require basic procedures (such as precision cutting, drilling, tapping or punching) to fully finished components and assemblies, we can satisfy all of your extrusion requirements.
Visit us to find out what aluminum extrusions can do in your industry.