Overheating may limit the rate if the take-off
cooling is limited, or it may produce
degradation or make dimensional control and
sizing difficult. In such a case, stop all barrel
heat except in the rear zone as needed for
bite (input) control and cool the barrel if
necessary. (In a few cases, more barrel heat
will yield a cooler melt.) There is a
temperature below which the melt will not go
at a given screw speed, even if all the barrel
heaters are turned off.