Finite element method for flow in compression molding of thin and thick parts

Based on Barone and Caulk's model and a generalized variational functional, a finite element simulation was developed for the compression mold filling of thin and thick cavities. For solving the u-ν-p type equations, an element-based penalty method and a mixed formulation were implemented. Numerical results show that the new model gives better accuracy in velocity and velocity gradient than the Hele-Shaw formulation for cases where both models are appropriate. Predictions of velocity and its gradient by the model are compared with other FEM results and BEM solutions. Using a fixed mesh that covers the mold cavity, a new technique was developed for tracking the moving flow front. Temporary elements and nodes are generated for the filled part of elements intersected by the flow front. This method allows a smooth representation of the flow front and has exact boundary conditions on the flow front. The scheme is demonstrated for compression molding of elliptical and L-shaped charges.