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Study of polymer melt flow in sequential injection molding process
Author(s) -
Chen S. C.,
Chen N. T.,
Hsu K. S.,
Hsu K. F.
Publication year - 1996
Publication title -
aiche journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.958
H-Index - 167
eISSN - 1547-5905
pISSN - 0001-1541
DOI - 10.1002/aic.690420622
Subject(s) - materials science , melt flow index , polystyrene , weld line , flow (mathematics) , molding (decorative) , polymer , composite material , control volume , core (optical fiber) , mechanics , finite volume method , volumetric flow rate , welding , physics , copolymer
Experimental studies of polymer melt flow in the filling and post‐filling stages of the injection molding process were performed using the sequential injection of transparent and colored polystyrene resin. Effects of fountain flow in the filling stage, geometrical factors caused by edges and corners, as well as flow through contractions and expansions, were identified. Significant polymer melt flow which increases with increased packing pressure was observed in the post‐filling process. The melt flow is more concentrated around the gate area than away from the gate. It was also found that the polymer melt flows across the gap center, resulting in partial annihilation of the weld line. Simulations based on the control‐volume/finite‐element method employed within each gapwise layer combined with the dual‐filling‐parameter technique were developed to trace the advancements in melt fronts for both skin and core materials. Numerical simulations show reasonable consistency with experimental results in both skin and core material distribution. If the edge effect is taken into account using a shape factor as a geometrical correction, the simulation accuracy is further improved.