METHOD OF INJECTION MOLDING PREFORM AND APPARATUS THEREFOR.

摘要

An injection molding apparatus has an injection molding station (14) and a cooling and takeout station (16). In the injection molding station (14), a neck cavity die (50), an injection core die (60) and an injection cavity die (42) are clamped for injection molding a preform (1). Then the injection cavity die (42) is released from the preform at a relatively high temperature. While the preform (1) is cooled by the injection core die (60) and the neck cavity die (50), the preform (1) is conveyed to the cooling and removing station (16). A new preform (1) is injection molded at the injection molding station (14) while the preform (1) continues to be cooled at the cooling and takeout station (16). After the preform (1) has been cooled to a temperature at which takeout can be made, the injection core die (60) is released from the preform by a stroke sufficient to produce a gap between a core pin (52) thereof and an inner wall of the preform (1). Then the neck cavity die (50) is opened and driven for permitting the preform (1) to be taken out. After injection molding of a subsequent new preform (1) is completed at the injection molding station (14), a rotary disk (30) is rotatingly driven in an opposite direction to the preceding direction of rotation so that the injection core die (60) and the neck cavity die (50) are changed at the respective stations (14, 16).