Packing of material along flow path in injection moulded container

Abstract

The distribution of material (weight) along the flow path in an injection moulded cylindrical container was quantified by cutting the container into five segments. Moulding conditions were varied and eight different polypropylene grades were used. The total weight increased and the weight distribution remained nearly uniform when increasing the packing pressure. Increasing the packing time above a certain limit, however, mainly packed material close to the gate. The weight distribution was also affected by material parameters, such as shear viscosity and degree of nucleation. The shrinkage and the compressive strength of the container were related to the weight distribution. In particular, the compressive strength was highly correlated with the weight of the segment at the end of the flow path. PRC/1752