Jetting phenomena in injection mold filling mold filling

Abstract

Abstract Experimental studies of injection molding of polymer melts have classified two regimes of mold filling–simple filling and jetting. In this paper we have examined a wide range of polymer melts and mold designs in an attempt to devise a criterion for the transition between these regimes. This criterion is found to be related to the extrudate swell d , gate diameter D , and small cavity dimension at the gate h . For isothermal mold filling, if d / h exceeds 1.0, the‐melt will contact the mold, stick to it, and induce a simple mold filling regime. The variation in behavior in vertical and horizontal mold filling is considered, as is the influence of barriers near the gate. For the non‐isothermal mold case, the manner of filling is similar, and the criterion for jetting remains the same, The die swell behavior in the non‐isothermal case is complex.