Finite element analysis of injection molding

Injection molding of plastics involves the transient monisothermal flow of a molten polymer into a cold-walled cavity, under high pressures, where it is cooled and solidified. The material at different locations of the final part experiences greatly different thermomechanical histories and as a result exhibits anisotropic properties in both the flow and gapwise directions. The anisotropy is associated with molecular orientation and structure induced formation during flow. The formation of a solidified layer at the wall and the fountain flow behind the advancing flow front have a significant impact on the experimentally observed anisotropy of molded parts. Also, when two flow fronts collide to form a weldline the flow induced orientation parallel to the weldline reduces the mechanical strength of the part.