A methodology for flow-front estimation in LCM processes based on pressure sensors

Liquid Composite Molding (LCM) processes offer nowadays considerable advantages for composite manufacturers; nevertheless, their robustness is still an open issue, since part quality is sensitive to slight material and process variations, mainly arising during preform impregnation. An accurate monitoring system is thus required for early identification of filling troubles and potentially adoption of control actions. This work proposes an approach for resin flow monitoring, based on a combination of a sensing system and numerical modeling, which can be easily implemented into a generic LCM process. Using pressure data provided by few sensors placed in strategic positions inside the mold cavity, the developed methodology enables reconstruction of flow-front patterns at any impregnation time, without simulation of cavity filling. The effectiveness of the methodology is demonstrated by two test cases, which validate the approach through comparison between real and estimated flow-front profiles. Potential and limitations of the method in presence of flow disturbances have been studied through several virtual experiments, defining the range of applicability and key issues for future development.