NUMERICAL-SIMULATION AND EXPERIMENTAL-VERIFICATION OF MELT FRONT ADVANCEMENTS IN COINJECTION MOLDING PROCESS

Experimental studies of polymer melt flow in the mold filling stage of the coinjection molding process have been carried out using sequentia l injection of transparent and colored polystyrene resin. Simulations are also developed to predict the melt front advancements of both skin and core melts. A control volume/finite element method employed withi n each grid layer of the gapwise direction is applied to trace the mel t front advancements for both skin and core materials. Numerical simul ations show reasonably good consistency with experimental results in b oth skirt and core material distribution. However, the simulation accu racy can be improved further if edge effect is taken into account usin g the shape factor as a geometrical correction.