Injection molding nozzle method using a terminal locating and sealing key

摘要

A method of making an integral heated nozzle (10) using a terminal locating and sealing key (72). A spiral portion (56) of an electrical heating element (54) is press fitted into a spiral groove (50) in the cylindrical outer surface of an elongated inner portion (12). The remaining outwardly extending terminal portions (58) of the heating element (54) are inserted through two holes (80) in the key (72) and the key is pushed inwardly to a position against the inner portion (12). The key (72) has a pin portion (76) which is received in a matching hole (78) in the inner portion (12) to exactly determine the length of the spiral portion (56) of the heating element (54) and accurately locates the terminal portion (58) of the heating element (54). An outer collar portion (32) having a slot (74) in which the key (72) is received is then mounted in place around the rear end (14) of the inner portion (12). A thermosetting ceramic sealant (82) is applied in the space (46) between the inner and outer collar portions then heated to integrally joint them together. The key (72) fits in the slot (74) in the outer collar portion (32) to prevent leakage of the liquid sealant (82) out through the slot (74).