Plastic extrusion is a process in which raw plastic is melted (partially) and formed into a continuous process. This process starts by feeding plastic material (after mixture or agglomerator) from a hopper into the barrel of the extruder. The material is gradually melted by the mechanical energy generated by turning screws and by heaters arranged along the barrel. The molten polymer is then forced into a die, which shapes the polymer into a shape that hardens during cooling through water.