Aluminum extrusion has become an important feature in construction because of its cost benefits and structural integrity. Additionally, aluminum is prized for adding metal accents to glass surfaces. Because aluminum extrusion allows for complex shapes on long continuous pieces, it can be exploited for numerous different construction materials.
The Extrusion Process
Extrusion is a process of shaping different molten materials, like metals or plastic, by forcing them through shaped designs at high pressures. Because of the process’s flexibility, there are a number of methods for performing it, including hot or cold, and continuous or semi-continuous.
A really simple analogy for extrusion would be a pasta machine. The prepared dough is sent through a press, which emits long, continuous strands of spaghetti. Metal extrusion is very similar, except on much larger scale. A mostly automated process involves workers melting down a metal to its molten form, then transferring it to the extrusion machine. The extrusion machine then forces the molten metal, by way of either hydraulic or mechanical power, through a steel die at high pressure. If it’s a continuous extruder, the press will continue to force the metal in one long, continuous section until the piece is done. If it’s semi-continuous, the press will cut off the pieces one by one as the metal is forced through the die. The finished pieces are then transported further down the assembly line for cleaning and finishing.
Costs for extrusion are limited to die molding, materials and manpower. Because an extrusion press can be outfitted with different dies, a manufacturer investing in the press will see longterm use. Steel dies vary in price but can be expensive for more intricate, precision varieties. With aluminum extrusion, the customer is fortunate to be using a relatively inexpensive metal that also has desirable strength capabilities. Although not on the level of a case-hardened steel, aluminum’s structural integrity is quite robust while remaining light, which is why it sees use in aerospace and construction applications.
Extruded Aluminum in Construction
Extruded aluminum products are versatile, both in application and production. Manufacturing extruded aluminum can be done by either cold or hot processes, continuously or semi-continuously. Lightweight extruded aluminum paneling or guide rails are common for trailer, shed and furniture construction, but denser aluminum structures are becoming common.
Recent construction in Chicago has employed over a million tons of extruded aluminum parts. Architects of recent high profile projects going up in “The Loop,” the Second City’s famed business district, have spoken of consciously trying to fit their buildings into Chicago’s Art Deco style, while retaining a contemporary feel. An executive V.P. at Lohan Caprile Goettsch Architects said that extruded aluminum was a “perfect choice,” to maintain this classic feel, while also serving utilitarian ends. “The extruded profiles are thermally improved, so heat doesn’t transmit through the curtainwall system,” he said.
Extruded aluminum is not just limited to exterior design and function, either. Lighting fixtures, elevator shafts and stairwells all employ many different applications. While aluminum can’t make up the basic frame skeleton of a building, it accents and aids the structure in the interior. Integrated extruded aluminum design features in almost all areas of building construction, including structural mechanical, plumbing and others.
Additional bonuses to using extruded aluminum are the reusability and recyclability of the material. It is a product that is fairly easy to re-appropriate or to refashion into another use, or properly melt down and completely recycle. This makes it additionally desirable to environmentally-conscious architects and manufacturers.
Aluminum Extrusion Showcase, “High-Rise building the Green Way is Transforming Chicago’s Skyline.”http://www.aec.org/exapps/greenbuildingdesign.html"