Comparative analysis of different process simulation settings of a micro injection molded part featuring conformal cooling

摘要

Process simulations are applied in all fields of engineering in order to support and optimize the design and quality of products and their manufacturing processes. Micro injection molding is not an exception in this regard. Simulations enable to investigate the process and the part quality. In the reported work, process simulations using Autodesk Moldflow Insight 2015 are applied to a micro mechanical part to be fabricated by micro injection molding and with over-all dimensions of 12.0 × 3.0 × 0.8 mm~3 and micro features (micro hole, diameter of 580 μm, and sharp radii down to 100 μm). Three different simulation models are established: a version including the part without the surrounding mold block, an advanced version including the mold block and conventional cooling channels, and a third version alike the second with additional conformal cooling for efficient thermal management. The implementation strategy for these configurations is presented focusing on the application of a multi-scale mesh with mesh sizes of 100-800 μm, 50 μm, and 100 μm for feeding system, gate area, and the micro component, respectively. The three models are compared with each other to demonstrate the influence of the implementation of the actual mold block, conventional cooling, and conformal cooling. In the comparison, characteristic quality criteria for injection molding are studied, such as the filling behavior of the cavity, the injection pressure, the temperature distribution, and the resulting part warpage. Additionally, the analysis of the cooling channels exploiting computational fluid dynamics is introduced as helpful tool for the mold design process. It is observed that the comprehensive implementation of the actual injection molding system and conditions is highly relevant at sub-mm/micro dimensional scales, and that the level of detail of the model influences the simulation outcome. Warpage of the micro component in the range of 85-105 μm could be simulated depending on the simulation configuration.