Maximum output will, of course, be achieved at maximum screw speed and torque as shown
schematically. also shown are some of the superimposed lines of constant melt temperature,
which indicate that reducing extruder screw speed and increasing extruder torque gives rise to lower melt temperature - and consequently reduced mixing intensity - due to reduced shear rate and residence time respectively. Product quality constraints ormaterial intake limits may require that the extruder is operated
below its maximum potential output.
Over the past two decades, significant steps have been made by extruder manufacturers to improve
the serviceability and output of a unit size machine and hence improve its cost effectiveness. The
technology has moved forward rapidly in terms of manufacturing techniques, torque transmission,
control systems, materials of construction, reliability and process expertise. A number of these