Modeling compression molding of all-thermoplastic honeycomb core sandwich components.: Part A:: Model development

The compression molding process is studied with the aim of modeling the instantaneous degree of face-core bonding in all-thermoplastic sandwich components during molding. The theory of bonding is briefly discussed and it is concluded that for most thermoplastic materials, processing is performed at temperatures where full bond strength is seemingly immediately established at positions in full face-core contact. A two-dimensional model is developed to predict increase in contact area due to flow of melted core material during molding. Further, heat transfer during processing is modeled in order to determine the extent of melted core material. The two models are coupled into one process model and a numerical example is presented illustrating the predicted behavior of polypropylene-based sandwich components in compression molding. The process model suggests that the face-core bond strength may be significantly increased through flow of the melted core wall.