In the dictionary the word ‘extrusion’ is defined has something forcibly exited through something else, for instance an aluminum shape forcibly pushed through a mold to create a new shape. Die-cast models are made using a similar process, as are many thousands of other items and appliances. The process of extrusion was first used by Joseph Bramah in 1797, when he invented the idea of using a pre-heated piece of metal—which softened it—and then pushing it through a mold hole or die, using a plunging fashion. When Thomas Burr built a hydraulic press in 1820 the practice of extrusion entered a period of further development. His methods involved ‘squirting’ the metal through the press at high velocity to create the new shape of the piece. More than sixty years after Burr adopted his methods of extrusion, Alexander Dick—in 1894—expanded the practice, even further, to include brass alloys and copper.
How the Process Works
Initially, the metal to be used in the process has to be heated up in order to make it more pliable. The piece of metal is then loaded into the press container where a block—known as a dummy block—is placed directly behind the metal. The press comes down and the metal is shaped by being pushed heavily through the die cast. This process is used in both warm and hot extrusions, but there is a cold extrusion process which is also used. This process simply keeps the metal at room temperature instead of using heating methods to warm it up before it is pressed. There are some advantages cold extrusion in comparison to the warm process and one main advantage is that it negates the oxidation process and offers a more strengthened result because the metal was worked when it was cold.
Aluminum extrusion suppliers are often given blueprints and models of their intended ‘target’ and are experts in the creation of appliances, items and devices using the extrusion method. Whilst extrusion is extremely popular as a method it is not without its faults and one of them is that it does produce defects or impurities in the finished piece. It can be likened to an engine block which has a crack in it. The engine can become defective simply because it has an impurity.
To locate trusted local aluminum extrusion suppliers, contact Howard Precision for a list of their products, services and prices.
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