Single Screw Plastic Extruder

A single screw extruder is a machine used to form a plastic product into the required shape. The machine heats the plastic raw material (e.g. PVC) to its melting point, after which it is pushed through a die that gives the material its shape.Single screw extrusion uses one screw within a cylindrical barrel to continuously push plastic through a constant profile die (Figure 12.7). Production rate is typically measured in mass per hour (lb/hour or kg/hour) and is controlled by the screw speed of the machine.The principal function of a single screw extruder is to build up pressure in thepolymer melt so that the polymer can be extruded through the die. Most of the single screw extruders are plasticating which mean that the solid resin balls or powders melt in the screw due to the pressure.