On the performance of micro injection moulding process simulations of TPE micro rings

Micro injection moulding (µIM) process simulations can be used as powerful tool for the optimization of the design of mould, part and process. However, numerous scale effects introduce relevant challenges in terms of both validation and accuracy of the simulations [1-2]. In this research, a case study based on µIM of thermoplastic elastomer (TPE) micro rings for sensor applications was treated. Injection moulding process simulations using Autodesk Moldflow Insight 2016® were applied with two main tasks: the first was the prediction of main parts defects. The second was the forecasting of the effects of the main injection moulding process parameters on the part geometrical accuracy. A 3D multi-scale mesh was used. The outcomes of the simulations were compared to real moulded parts based on SEM inspections and focus variation measurements. The results show that the model was capable of accurately capturing the position of the micro ring weld lines and air traps. Process simulations also correctly predicted the effects of the investigated process parameters on the part dimensions. The average deviation between real parts measurements and simulations results was 2 µm, demonstrating that single digit micrometric simulation accuracy was successfully achieved.