Metal extrusion is a process that is used to create products that have a fixed cross-sectional profile. Metal extrusion units in India use a die with the desired cross-section, and the material for extrusion is pushed through it. With the metal extrusion process, not only can products with complex cross sections be manufactured, but this process can also work with brittle raw material, owing to the fact that the material only has to encounter shear and compressive stresses. Another advantage of extrusion is the excellent surface finish of resultant products as well as the fact that extrusion in metals also helps increase the strength of the material.
Drawing is another such process which pulls the material through dies, utilizing the tensile strength of the material. Multiple stages are usually needed in this method and it is limited in terms of the amount of changes that can be made. Drawing is hence, limited to simpler shapes and is a main way of producing metal bars, tubes or wires.
The process of metal extrusion can either be semi-continuous or continuous and can be performed with both hot and cold materials. The products of this process are referred to as â€œextrudatesâ€ and metal extrusion units in India commonly extrude materials like foodstuffs, play dough, concrete, ceramics, polymers, and metals.
As there is no way for supporting the centre barrier in a die, it becomes difficult for hollow cavities to be produced within extruded material, using a simple flat extrusion die. So for a hollow cavity to be made, the die begins to shape itself with a profile that supports a centre section. It then changes internally along its length to form the final shape, with the suspended centre piece supported from the back of the die. The material being extruded then flows around the supports and then fuses to form the desired final shape.