INJECTION-MOLDING OF LDPE BASO4 BLENDS - MOLD FILLING STUDIES/

The injection mold filling behavior of a blend of low density polyethy lene (LDPE) and barium sulphate (BaSO4) was studied experimentally and compared with that of pure LDPE. The method of short shots was used t o analyze the mold filling behavior. An experimental study using a ful l factorial design was implemented with the following factors: mold te mperature, injection speed and injection time. Experimental results an d computer simulation predictions of the mold filling stage were found to be in acceptable agreement. The produced short shots with the LDPE /BaSO4 blend have significantly lower percentages of volume filled tha n those of the corresponding short shots with the pure LDPE. The incre ase in the melt viscosity and density of the polymer resin with the ad dition of BaSO4 cannot be neglected when producing injection molded ar ticles with LDPE/BaSO4 blends. To study the deviations between the exp erimental results and the computer simulation predictions, a factorial numerical study was completed. The results show that the simulation p redictions ale significantly affected by the accuracy of the polymer m aterial properties.