Experiments with a corotating twin-screw extruder show that a considerable throughput increase can be achieved by feeding the extruder with preheated pellets' The use of preheated pellets is also advantageous in that, for a given throughput, the extrusion of preheated pellets requires a lower torque. Thus, when shifting from cold to preheated pellets, the screw speed can be lowered until the original torque is again reached. As a result, the temperature of the exiting melt is lower as well. The use of preheated pellets thus gives an extra degree of freedom in terms of the maximum throughput of a given extruder and control of degradation-sensitive polymers. © 2005 Society of Plastics Engineers.