RAPID INJECTION MOLDING OF CABLE TIES

摘要

A nylon cable tie (16) having a head (18) and a strap (20) terminating in a tip (22) is formed in a mold cavity defined by a first mold part (10) combined with a second mold part (12) by injecting molten nylon material into the mold cavity through an insulated runner system (40) and a gate that converges from the runner system toward the mold cavity and does not have a hot tip adjacent thereto. The mold parts (10, 12) are separated while retaining a portion of the head (18) in a head region (24) in the first mold part (10) and a portion of the tip (22) in a tip region in the second mold part (12), in order to separate the head (18) from the second mold part (12), to separate the tip (22) from the first mold part (10), and to separate a major portion of the strap (20) from the first and second mold parts. The mold parts (10, 12) are further separated while retaining said portion of the head (18) in the head region (24) to thereby remove said portion of the tip (22) from the second mold part (12). The head (18) is ejected from the head region (24) by protracted ejector pins (32) that penetrate the head region from within the first mold part (10). A component (34) containing a nozzle coupled to a source of compressed air and positioned closely adjacent the head region (24) is protracted from the first mold part (10) and pushes on the strap (20) to push the ejected head (18) of the cable tie (16) away from the ejector pins (32). The cable tie (16) is then ejected from between the mold parts (10, 12) by imparting against the ejected head (18) of the cable tie a forceful stream of compressed air directed from the nozzle in the component (34).