On the performance of a viscoelastic constitutive model for micro injection moulding simulations

Abstract

The numerical simulation of the injection moulding process involving microstructures presents several challenges, mainly due to the surface effects that dominate the flow behaviour at the microscale. In this paper a new approach, which employs weld lines as flow markers, is used to evaluate whether the numerical codes that are normally used to simulate the conventional injection moulding process, are suitable to characterize the melt flow patterns in the filling of micro features. The Cross-WLF viscous model and the Giesekus viscoelastic model were evaluated using 3D models of a micro part implemented in two different numerical codes. A micro cavity was designed in order to compare the results of numerical simulations and experiments. While the viscous simulations were found to be inappropriate for multi-scale structures, the accuracy of micro filling predictions was significantly improved by implementing a viscoelastic material model.

Keywords

• Rheology
• Modeling and simulation
• Micro injection moulding