The extrusion machine, or extruder does this process. This heat softening is called by various names, such as ‘plastication’, ‘plasticization’ or ‘thermal softening’. Most extruders are single screw machines. It is the screw which forces the material towards, and then through, the die. Shape is impart-ed by the die, and/or by post-extrusion forming, and then the product is set to