Determination of the Transition Temperature at Different Cooling Rates and Its Influence on Prediction of Shrinkage and Warpage in Injection Molding Simulation

In injection molding simulation the phase change from melt to solid state is usually simplified by using a so called transition temperature. In the present work, the transition temperatures of several amorphous and semicrystalline polymers were determined using DSC-runs at different cooling rates. The transition temperature was described as a function of cooling rate. The obtained transition temperatures of the semicrystalline polymers were used in injection molding simulations with the commercial software package Autodesk Moldflow Insight 2010 to calculate the shrinkage and warpage of box-shaped test parts. The simulation results were compared with the experimental values of optically measured injection-molded boxes. The results showed a strong influence of the transition temperatures on the simulation results of a 3D model and a very low influence for a 2.5D model. Transition temperatures obtained at higher cooling rates improved the 3D simulation results for several dimensions. (C) 2011 Wiley Periodicals, Inc. J Appl Polym Sci 123: 1162-1168, 2012