Starve feeding
Vol. 26 #2, September 1999
Twin screw extruders are normally run starve fed, so the operator is free to adjust the screw speed for a certain throughput rate, but there is a proper operating range of screw speed allowable. If the screw speed is too high, the extruder becomes unfilled of polymer and surging may result. If too low a screw speed is run, the screw fills up and an over torque condition may result. For most mixing cases, to reduce overheating and for better energy efficiency, it is best to run toward the higher fillage, lower screw speed end of the range, at about 80 to 85% of the maximum torque. Some exceptions to this are when high screw speeds are needed for very intensive high shear mixing, for many devolatilization cases and when polymer backs up into an open port.
- Carl Hagberg, NFM/ Welding Engineers
See also:
- Extrusion feeding
- Polymer devolatilization
- Twin screw extruders design and operating characteristics
Return to
Consultants' Corner