Single Screw Extruders

• Consists of a screw in a metal cylinder or barrel



• One end of the barrel attached to the feed throat while the other end is open



• A hopper is located above the feed throat and the barrel is surrounded by heating and cooling elements



• The screw itself is coupled through a thrust bearing and gear box, or reducer, to a drive motor that rotates the screw in the barrel



• A die is connected to the “open” end of the extruder with a breaker plate and screen pack forming a seal between the extruder and die.

During extrusion…

• Resin particles are fed through the hopper, through the feed throat of the extruder, and into the extruder barrel


• The resin falls onto the rotating screw and is packed in the first section or feed zone of the screw


• The packed particles are melted as they travel through the middle section (transition or compression zone) of the screw, and the melt is mixed in the final section or metering zone.


• Pressure generated in the extruder forces the molten polymer through the die.

Components of the extruder hardware

• Drive system


• Feed system


• Screw/ barrel system


• Head/ die system


• Instrumentation and control system