Plastics extruders grooved barrel

Spalding, M. A., Hyun, K. S., and Hoffmann, R., An Experimental Investigation of Solids Conveying in Smooth and Grooved Barrel Single-Screw Plasticating Extruders, SPE ANTEC Tech. Papers, 44, 136 (1998)... 

Within the feed section, as well as elsewhere in the extruder, friction between the plastic and the barrel is responsible for conveying the plastic forward. Without this friction, the plastic would simply rotate with the screw, staying in place rather than moving forward. Grooving of the feed section of the barrel is sometimes used... 

The grooved barrel section has to be cooled well enough to avoid premature melting of the plastic in the grooves this reduces energy efficiency and adds to the complexity of the extruder. 

For many years, plastic extruder feed zones had smooth barrels, but feed zone inserts with grooves to restrain pellet rotation were introduced in Europe in the 1960s and have grown in application, particularly in combination with barrier screws, but less so in North America. 

Figure 6. Average melt pressure courses in grooved feed zone extruders with diffo ent grooves in the plasticizing barrels specific throughput 4,30 kg-min/h.

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