POWDER METAL INJECTION MOLDING-THE EFFECT OF RUNNER DESIGN ON FILLING IMBALANCES AT DIFFERENT FILL SPEEDS

摘要

Imbalances occur in powder injection molding of multi cavity molds, which are sometimes opposite to the shear induced imbalances of conventional plastic materials. In a previous study it was found that melt rotation technology not only reduced imbalances, but also helped reduce differences between the mechanical properties of parts molded in multi-cavity molds. This paper presents the results of a study that expands on a previous work to include effects of fill rate, additional variations in runner geometries, and designs of melt rotation technologies for eliminating the variations.