MOLDING DEVICE FOR BELLOWS TYPE MOLDED FORM

PURPOSE:To permit cooling of a core and facilitate the mold releasing of a molded form, by a method wherein a part, pinched between a pair of split cavity blocks, and another part, serving the function of a core for an opening at one end of a molded form, are formed at the tip end section of a slide core pin while an air passage, communicating a compressed air source with the outside of the tip end of the core, is provided in at least one of the slide core pin and the core. CONSTITUTION:The inner surfaces of a large diametral side opening 3 and a bellows 4 among the openings at both ends of a molded form 1 are molded by a core 11, however, the inner surface of a small diametral side opening 2 is molded by the tip end section 35a of a slide core pin 35. An injection molding machine is operated and molds are closed interposing the core 11 between the molds while positioning a movable side split cavity block 10B through the guidance of a guide pin 23 and a guide bush 24, then, molten resin is injected to supply it into a molded form gate 18 from the nozzle of the injection molding machine through a sprue bush 15, a hot runner block 16 and a hot runner tip 17 and mold the molded form. The molds are opened after finishing the molding. In this case, compressed air passes through the air passage 34 and is injected outwardly from the tip end of the core 11 whereby the core 11 is cooled and the excessive temperature rise of the core 11 may be prevented.