If you have ever seen those little kiddie toys where they have the plastic ‘table’ and little holes for shapes that are cut out and the kid takes a shape and pushes it through the corresponding hole, that is the best way to explain extrusion. However, there is one vital stage missing from that explanation and that is, with extrusion, you are actually creating the shape by pushing it through the hole.
Aluminum is one of the softest and most easily pliable metals on the planet. Because of those features it is one of the most popular and commonly used materials on the Earth and is commonly used in the mixing of alloys, using other metals. The toy with the holes is comparable to the process known as extrusion, as previously mentioned. Extrusion works in a way that pushes the prepared aluminum through a predetermined mold shape and when it comes out the other side it is shaped in the same way as the mold.
What Kinds of Extrusion are there?
There are actually quite a few types of extrusion. Generally the process always begins the same way, with the stock being heated—this is for warm or hot extrusion only—to a certain acceptable temperature. The press is made ready and a ‘dummy’ block is set behind it on the press. The press is then activated and basically it slams through the mold, taking the pliable aluminum with it and creating a new shape from the metal. Hot extrusion includes various metals and other elements, including nickel, titanium, copper, and steel and temperatures between 350 and 2000 degrees centigrade. With warm extrusion the temperatures never go above 975 centigrade and only as low as 424.
Cold extrusion is more or less exactly one would imagine, with no heat applied to the metal whatsoever. This process is done only at room temperature and it has the advantage of creating far less oxidation than the heated methods.
There are some possibilities of defects when it comes to all versions of extrusion but to minimize it Surface cracking is one of the main issues that the process can have, as well as internal cracking but there is no specific pattern.
To find a reliable company to supply your extruded aluminum shapes, contact Howard Precision for a list of their products, services and prices.