Injection molding apparatus

Abstract

Apparatus for forming objects from molten material includes a mold frame and a movable mold side having complementary faces that define molding cavities. The mold frame includes a mold housing having an internally heated manifold which has a plastic distribution channel for feeding plastic to an injection nozzle passageway having a restricted discharge nozzle that discharges the plastic into a molding cavity. Within the injection nozzle passageway is a heater probe which has an internal heater, preferably an electrical cartridge heater. The probe is secured by an integral seating flange to the mold housing to hold the probe coaxially aligned in the injection nozzle passageway and to hold the probe against shifting with thermal expansion and contraction of the manifold. The integral flange may be positioned at or adjacent the exterior of the mold so that it can be pulled outwardly to remove an elongated body of the probe from the nozzle passageway for easy replacement of the internal cartridge heater disposed within the interior of the probe. The electrical cartridge heater is substantially lower in cost than external electrical band heaters used heretofore for heating plastic flowing internally through a probe.