Aluminum extrusion is the process of causing deformation of the metal by squeezing a solid piece of metal through a die or a chamber to form a different shape. Some of these shapes can include: long tubes, rods, hollow sections, parts with asymmetrical, complex cross-sections, etc. The extrusion pressure is provided through a ram by pneumatic or hydraulic means.
Aluminum extruded parts are very commonly used in things such as electrical wiring and cabling. They are used to hold wires together in a specific configuration such as in: decorative items, fins for heat conduction in motors, heat sinks, collapsible tubes, aluminum cans, fire extinguishers, and gear blanks, etc. The components can be mass-produced, cut to the required lengths (with even a hacksaw blade) and are economical and light.
In the process of aluminum extrusion the aluminum pieces are softened up by heating them to about 900° F; the pieces are then lubricated so they won’t stick to any of the machinery components they may come in contact with. A ram is used to apply pressure against a block which forces the aluminum into the extrusion die opening. Nitrogen gas is then injected to cool the die and to help stop the hot aluminum from oxidizing.
When the aluminum is extruded from the die its temperature is monitored closely as different types of aluminum alloys need to be at a certain temperature for the quickest extrusion. When the metal leaves the die the extrusion is pulled onto a leadout table by a machine that is called a puller. The aluminum extrusion is cooled by the air or by air and water.
When the aluminum has been completely extruded a new aluminum ingot is put into the chamber and is welded to the end of the extrusion, allowing the process to continue. The extrusions can then be cut to the required size and can be stretched. The aluminum can be hardened in an oven. After the extrusion is completely cool the metal can be deburred and the extrusions are ready to be used.
Aluminum extrusion lets you form many different shapes of aluminum components without having to melt down and cast the metal. Aluminum extrusion can also be done either at room temperature. When the metal is cold extruded, problems of oxidation are avoided. It is important that the metal deforms and flows uniformly without cold tearing, warping or tearing. Extrusion can be done both vertically and horizontally.