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Cavity Fill Balancing Technique for Rubber Injection Molding
ISSN: 0148-7191, e-ISSN: 2688-3627
Published April 14, 2015 by SAE International in United States
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Balancing the fill sequence of multiple cavities in a rubber injection mold is desirable for efficient cure rates, optimized cure times, and consistent quality of all molded parts. The reality is that most rubber injection molds do not provide a consistent uniform balanced fill sequence for all the cavities in the mold - even if the runner and cavity layout is geometrically balanced. A new runner design technique, named “The Vanturi Effect”, is disclosed to help address the inherent deficiencies of traditional runner and cavity layouts in order to achieve a more balanced fill sequence.
Comparative analysis of molded runner samples reveals a significant and positive improvement in runner and cavity fill balancing when the Vanturi Effect is integrated into the runner design. Research results indicate that a viable and useable relationship exists between the fluid-like characteristics of the rubber flowing through the runner as the rubber flows into and through a specific geometric shape incorporated into the runner layout - which introduces the Vanturi Effect - resulting in improved balanced filling of the runners and cavities.