A Visual barrel system for study of reciprocating screw injection molding

A 'visual' barrel system has been developed to promote the understanding of polymer behavior in a reciprocating screw injection molding machine. This system allows the dynamic status of the polymer inside the injection barrel to be conveniently visualized though photography and video recording, and the corresponding material conditions can be measured via a computerized data acquisition system. High density polyethylene (HDPE), a commonly used thermoplastic, is chosen to demonstrate the polymer melting behavior in injection molding. Effects of processing conditions on the melting behavior are analyzed, suggesting that the modeling of the plastication phase should not be treated simply as an extrusion process. The system, therefore, can not only assist in the understanding of the process but also can be used to verify quantitatively the modeling and optimization of an injection molding system.