A 3-D numerical study on injection molding filling

This paper presents the development of a three-dimensional (3-D) injection molding filling simulation using different algorithms and finite element types. Two numerical models, the mixed model and the equal-order model, were used to solve the Stokes equations with three different tetrahedral elements (Taylor-Hood, MINI, and equal-order). The control volume scheme with the tetrahedral unite element mesh was used for tracking advancing melt fronts. The numerical simulation was validated for the mold filling of a precision optical lens. The numerical simulation agreed very well with the experimental results. As a new application area, a two-step, macro-micro filling approach was adopted for the filling analysis of a part with a micro-surface feature to handle both macro and micro dimensions while avoiding an excessive number of elements. Comparison between the numerical predictions and experimental data suggests that the flow velocity and heat transfer coefficient on the mold surface plays an important role in determining the flow behavior and penetration length within the micro feature.