Plastic extrusion is the process by which small pieces of plastic, called granules or pellets, are extruded through dies to create a desired shape. Although plastic extrusion was only introduced in the 20th Century, it’s use has extended across a variety of industries worldwide. Shapes commonly produced through the process of plastic extrusion include pipe, tubes and profiles; however, the extrusion process is not limited to this.
In order for the extrusion process to take place, plastic is forced through a channel/barrel by a rotating screw. The barrel is heated up to around 200 degrees Celsius, which causes the plastic to melt and this allows the plastic to be pushed through various dies. The amount of pressure applied within the extruding process can also affect the finished result. Therefore, the finished product and often the plastics strength, is dependent on the conditions/factors that the plastic were extruded in.
The various properties of plastics have meant that it is being frequently chosen, as it displays numerous qualities such as durability, strength, recyclability, affordability and resistance to the weather. These advantages have been recognised by various industries and therefore a variety of plastics including high density polyethylene (HDPE), low density polyethylene (LDPE), PVC, PETG, vinyl, butyrate, polystyrene and polypropylene are now being extruded.