Analysis of bubble formation during injection molding of polymeric foams by computational fluid dynamics simulations

Foam injection molding processes have received special attention in polymer industry. The size distribution of bubbles is an important parameter on the molding piece, which depends on the characteristics of the blowing process. This work proposes a computational fluid dynamics (CFD) methodology to analyze the formation and distribution of bubbles in a foamed polymer piece. The birth, coalescence, and breakup of bubbles during the filling process were included and related to the azodicarbonamide (ACA) decomposition. The results agree with experimental data and allow the prediction of shape, location, and predominant size of bubbles. The proposed methodology could also be used to study arrangements of bubbles in more complex geometries, which are directly related to the mechanical properties of the piece.