Hopper and Feed Port

The pellets of plastic are first transferred from storage to the hopper on the extruder, which serves as a reservoir to feed the solid particles into the barrel. The hopper can be a simple one like the one shown in Fig. 7.1. Most extrusion operations are automated at least to the point of having a vacuum hopper loader to bring material to the hopper. Specialized equipment is available to mix in color and other 

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Cooling is often provided at the hopper and feed port, to prevent premature melting of the plastic, which can create blockages that interfere with a consistent rate of flow of the plastic into the extruder. 

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