Worn barrel repair
Vol. 23 #3, December 1996
Repairing worn barrels by re-sleeving can result in poorer thermal conductivity from the barrel bore to the outer surface of the barrel. The magnitude of this effect is related to any gap that occurs between the sleeve and the barrel. With a good shrink fit on the sleeve this reduction in thermal conductivity can be relatively small. However, with longer sleeves it becomes difficult to maintain total contact between the pieces thereby greatly reducing heat transfer in or out of the barrel. This can result in poor temperature control as the thermocouple is somewhat "insulated" from the process. It also can result in reduced heating or cooling effectiveness. Often re-sleeved barrels can take longer to heat up at start-up.
- Jim Frankland, New Castle Industries
See also:
- Barrel and screw wear
- Further comments on barrel profiles
- Heating modes for extruder barrels
- On/off barrel cooling control
- Temperature control
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