Basic Screw Extrusion Process
Plastics extrusion is a high-volume manufacturing process in which raw plastic material is melted and formed into a continuous profile. Extrusion produces items such as pipe/tubing, weather stripping, fence, deck railing, window frames, plastic films and sheeting, thermoplastic coatings, and wire insulation. This process starts by feeding plastic material (pellets, granules, flakes or powders) from a storage hopper into the barrel of the extruder. The material is gradually melted. As the melt proceeds down the barrel of the extruder towards the die, it is forced through the die opening to form a shape. The extrudate is cooled in an air or water bath so that it hardens and can be pulled onto take-up rolls for storage.