On the applicability of micro-injection moulding simulations to multivariate integrated process/product optimization

As in conventional injection moulding, process simulation of micro-injection moulding (μIM) is a powerful tool for the optimization of the design of mould, parts and process. However, the miniaturized scale of the micro products introduces relevant challenges in terms of both validation and accuracy of the simulation results. In the present work, a case study based on the μIM process of thermoplastic elastomer (TPE) micro rings for sensors application is treated. Moulding process simulations using Autodesk Moldflow Insight 2016® were applied with the aim of predicting the effects of the variation of mould temperature, melt temperature, injection speed and holding pressure on the part geometry. The outcomes of the simulations were directly compared to real parts based on high accuracy optical measurements. The numerical model was calibrated by fitting simulations results to experimental observations taking into account the measurement uncertainty. The calibrated model was validated against the effects of the process parameters and then used to carry out a virtual optimization. The results showed that simulations correctly predicted the effects of the four investigated process parameters on the part geometrical accuracy, opening the door to profitable μIM virtual experiments.