Screw Geometry Design and Performance Effects on Fiber Breakage Study

Abstract

Long glass fiber pellets has emerged as a potential substitute for metals in the making of non-load bearing automotive structural components and panels for the past five years. Their weight can be reduced and the part design can be more flexible. Long fiber now finds its balance between the mechanical performance and the easiness of processing. Since maintaining the fiber length is crucial to the superior performance of the long fiber, it is crucial to consider the machinery design along the melt pathway, including the screw, nozzle, runner, and the gate so as not to pose high stress on the fiber causing breakage. We presented in this paper a simulation method to predict the fiber length degradation during the plastication of the injection molding process. The screw design and the processing setting proved to be important for the fiber breakage. This method serves as the missing element by considering the effect of screw and barrel, which has not been addressed before with injection molding simulation.