The process called plastic extrusion is commonly used to produce a variety of plastic tubes, profiles, sheets and other custom plastic shapes.
In order to produce the desired shape, a plastics are pushed through a die. In instances where layers of plastic are required a process of co-extrusion is actioned. This is where two or more extrusion machines help produce a single product. For example if a product requires a tough outer layer, the one machine might produce the bulk of the plastic extruded product and the other to produce the stronger outer layer.