PRACTICAL ASPECTS CONCERNING THE DEMOLDING MOMENT CALCULATION FOR INJECTED PARTS WITH EXTERNAL THREAD
Abstract: The phenomenon of adhesion represents an essential problem regarding the process of plastic injection process. Furthermore, when the plastic parts have various areas with thread (internal or external with various form i.e. trapezoidal or saw – take for example the classical case of a container's neck finish and the corresponding cap) a demolding moment occurs when the part is detached from the mold. In here, a theoretical step-by-step approach is proposed in order to determine this demolding moment. The approach is applied for different sizes of saw thread profiles. This key parameter of the injection process directly influences the design solution of the ejector system.
Key words: injected plastic part, demolding moment, saw thread form.
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