Automated manufacturing environment to address bulk permeability variations and race tracking in resin transfer molding by redirecting flow with auxiliary gates

Abstract

Liquid Composite Molding (LCM) processes inject a resin into a closed mold containing fiber preforms to manufacture a polymeric composite. Many a times, resin does not fully saturate the fiber perform causing one to discard the composite part as scrap. In order to make LCM processes more reliable, a scientific understanding of the resin flow and impregnation into the porous network containing fiber preform can lead to advanced manufacturing techniques which can rely on flow control approaches to improve the yield. The flow is usually controlled by redirecting the resin flow by strategically opening and closing auxiliary injection gates as dictated by the flow monitoring sensor system. There are various approaches to generating such strategies. Once such technique, scenario-based control, has exhibited the potential to compensate for flow disturbances such as race tracking. However, a flexible and reliable manufacturing environment is needed in order to carry out experiments in advanced LCM processing. For this, an automated Resin Transfer Molding apparatus was designed and built, containing all of the necessary components. Flow sensors allow for the monitoring of the fluid advancement. Individually controllable injection gates and vents allow for geometrical flexibility and flow control. The following study demonstrates usefulness of the manufacturing tool to implement, validate and uncover limitations of a scenario-based flow control approach with geometries of increasing complexity.