Abstract
Injected plastic parts with internal threads (round, trapezoidal or saw) can increase products functionality but if not carefully designed can add unforeseen costs into the manufacturing process. In this paper the authors presents a computation methodology of the demolding moment for two cases of plastic injected parts with internal saw thread. This key parameter of the injection process directly influences the design solution of the ejector system. As further work the author will try to validate this method through a set of practical experiments.
Keywords: injection molding; demolding moment; saw thread