ABSTRACT
Injection blow molding is, by definition, combining injection molding with blow molding. The parison or preform is injection molded at the first station. Once the outside skin of the parison is set up so that it will not fracture when the injection mold halves separate, the rotating table rises a set height, rotates either 120° or 90°, and then drops down to lay the core rod containing the injection-molded parison into the blow mold bottom half. Then the blow mold clamp closes, capturing the injection-molded parison, and the trigger bar inside the rotating table is activated to move forward a set distance. This trigger bar movement pushes the spring-loaded core rod body or tip to open, and air or another gas enters through the core rod and lifts the injection-molded parison from the core rod and, via the air or gas pressure, forms the hot injection-molded parison to the inside of the female cavity blow mold shape. The neck or finish (threaded or snap fit) of the injection-molded parison is formed in the injection mold station and is cooled or allowed to set up in the blow mold station. Once the blown shape is allowed to cool so that the blow mold shape is retained, the air or gas is exhausted. Once exhaust takes place, the blow mold clamp opens, and the rotating table carrying the core rod and the blow-molded product lifts to its set height and again rotates either 90° or 120° to the eject station.
