EXTRUSION
More plastic resin has processed through the extrusion process than through any other plastics manufacturing technique. This fact, however, is misleading. Very big amounts of plastics are processed by extrusion into pipes, films, sheets, coatings and so on. Extrusion is also used for producing pellets of thermoplastic materials. Therefore, the majority of plastic material produced in the world today has had at least one extrusion through an extruder. Then those materials will be used in other plastic processing methods, like injection moulding, blow moulding and other melt processing methods, including the extrusion. Extrusion is a typical method to produce continuous products (pipes, sheets, films, coatings) of different kinds of materials. The first extruders were developed for food and building materials industry. Nowadays very many materials can be extruded into products. In the area of technical materials the polymeric materials are the most common ones. During extrusion, a polyme...