| 摘要 |
An extrusion die-set is disclosed for extruding plastic film, in which the nozzle-lips (6,8) are heated, for the purpose of allowing production speed to be raised without losing film-quality. The heaters include aluminum rings (62,82) embedded in grooves in the dies near the nozzle lips. The surfaces (66,67,86,87) of the ring that face away from the nozzle lips are cut away, so that heat transfer to the bulk of the dies (60,80) is reduced. The disclosed heaters eliminate the problem of hot-spots and cold-spots around the circumference of the nozzle. The nozzle lips can run several degrees hotter than the bulk of the dies, using the disclosed heaters. |
