EXTRUSION PROCESS

The aluminum extrusion process actually augments the properties of aluminum, because it allows the creation of a final end product that is stronger and more resilient than components that must be assembled. It allows for the fabrication of products to various specifications and sizes, while being flexible enough to allow for design alterations, augmentations and additions.

The process also facilitates cost-efficiency of the use of aluminum, as it creates finished products that are either complete as a unit or can interlock or join with other strong metallic parts. This process allows designers and engineers freedom to create aluminum products in complex and intricate shapes, since the end product can be extruded as a final piece instead of requiring multiple ones that must be assembled.

The extrusion process also creates a natural finish - a thin layer of aluminum oxide - that forms on the surface of the metal as a result of the process. This naturally resilient and attractive finish can be improved with additional beautifying and weather-resistant finishes.

The extrusion process starts with the furnace, where aluminum billets are heated to the necessary point of malleability. The aluminum or aluminum alloy is heated to temperatures ranging 750 to 900 degrees Fahrenheit, at which temperatures it acts as a malleable solid.

At this point, aluminum is a soft solid that can be pressed through dies, using scaleable amounts of pressure - a process called extrusion. An extrusion press utilizes a hydraulic ram that applies between 100 to 15,000 tons or more of pressure. The extrusion press container chamber, which holds the billet, is made of steel. The aperture in the die represents the final product. The aluminum is pressed through the chamber and through the die to create the final, shaped profile.

Complex shapes may emerge from the extrusion press as slowly as one foot per minute. Simpler shapes can emerge as quickly as 200 feet per minute. As the extrusion leaves the extrusion die, quenching (or cooling) methods such as air, water sprays, water baths and mists are used to quickly cool it.

In conjunction with the quenching, pullers cut and move the extrusion to a cooling table or stretcher, where the extrusion is straightened and cut to the ordered length.