Method for stripping open ended bellows part from injection mold

A method for stripping a bellows part from an injection mold comprising the steps of:

• a) injection molding a bellows part having two open ends around a core pin, said core pin having a longitudinal axis and a first split cavity surrounding said core pin, said bellows part having an undercut portion;
• b) opening said first split cavity to permit said bellows part to be stripped from said core pin;
• c) expanding said bellows part outward from said core pin;
• d) gripping said bellows part at said undercut portion by a gripping means;
• and
• e) pulling said bellows part at said undercut portion by said gripping means to remove said bellows part from said core pin while said bellows part is expanded outwardly from said core pin, said gripping means comprising a second split cavity which grips said undercut portion of said bellows part, said second split cavity separating axially from said core pin to pull said bellows part from said core pin while said bellows part is expanded outwardly from said core pin.

A method for stripping an open ended bellows part from an injection mold comprising the steps of:

• a) injection molding a bellows part, said bellows part having a resilient portion located between a core pin and a first split cavity and a substantially rigid portion located between said core pin and a second split cavity, said substantially rigid portion having a first open end and an external undercut portion, said resilient portion having an inner surface and a second open end;
• b) opening said first split cavity to permit said resilient portion of said bellows part to be stripped from said core pin;
• c) passing compressed gas through said core pin to said inner surface of said resilient portion while said first and second open ends of said bellows part are closed off by said second split cavity and said core pin, respectively, thereby expanding said resilient portion outwardly from said core pin;
• d) gripping said undercut portion of said substantially rigid portion of said bellows part by said second split cavity;
• e) separating said core pin axially from said second split cavity, thereby pulling said resilient portion of said bellows part from said core pin while compressed gas maintains said resilient portion expanded;
• and
• f) opening said second split cavity to disengage said undercut portion of said substantially rigid portion of said bellows so that said bellows part may be ejected from said injection mold.

A method for stripping an open ended bellows part from an injection mold comprising the steps of:

• a) injection molding a bellows part, said bellows part having a resilient portion located between a core pin and a split cavity and a substantially rigid portion located between said core pin and a solid cavity, said substantially rigid portion having a first open end and an external undercut portion, said resilient portion having an inner surface and a second open end;
• b) opening said split cavity to permit said resilient portion of said bellows part to be stripped from said core pin;
• c) passing compressed gas through said core pin to said inner surface of said resilient portion while said first and second open ends of said bellows part are closed off by said solid cavity and said core pin, respectively, thereby expanding said resilient portion outwardly from said core pin;
• d) gripping said undercut portion of said substantially rigid portion of said bellows part by said solid cavity;
• e) separating said core pin axially from said solid cavity, thereby pulling said resilient portion of said bellows part from said core pin while compressed gas maintains said resilient portion expanded;
• and
• f) operating a stripper rod to push said bellows part out of said solid cavity.