METHOD FOR STRIPPING OPEN ENDED BELLOWS PART FROM INJECTION MOLD

摘要

A method for stripping an open ended bellows part from an injection mold has as a first step the injection molding of a bellows part. The bellows part has a resilient portion located between a core pin and a first split cavity and a substantially rigid portion located between the core pin and a second cavity. The substantially rigid portion has a first open end and an external undercut portion, and the resilient portion of the bellows part has an inner surface and a second open end. The first split cavity opens laterally to permit the resilient portion of the bellows part to be stripped from the core pin. Compressed gas passes through the core pin to the inner surface of the resilient portion of the bellows part while both open ends of the bellows part are closed off by the second cavity and the core pin. As the cavity and core portions of the mold separate, the second cavity grips the undercut portion of the substantially rigid portion of the bellows part, thereby pulling the resilient portion of the bellows from the core pin while compressed gas maintains the resilient portion expanded. Finally, the second cavity either opens or has a stripper rod to disengage the undercut portion of the substantially rigid portion of the bellows part so that the bellows part may be ejected from the injection mold.