Sensor placement study for online flow monitoring in liquid composite molding

On-line sensing can play an important part in controlling the quality of th e final product in any manufacturing environment, including liquid composit e molding (LCM). Having a sensor embedded within the part itself is often t he most effective means of monitoring its condition at various stages of ma nufacturing and even throughout its useful life. However, given their intru sive nature, there are practical Limitations imposed upon their size, quant ity and trajectory within the part. This study explores the possibility of using a single Lineal sensor to monitor the resin now front during the mold filling stage of LCM, and to detect the onset of void formation and the pr esence of dry spots within the mold, Experiments were conducted to characte rize the response of a fiber optic system previously developed for cure mon itoring. Simulations were then performed to determine the optimal placement of just one such sensor in a mold to demonstrate that sufficient informati on on the mold filling process could be obtained. The purpose of the simula tion work was to learn how to interpret the sensor response and, subsequent ly, use it to control the LCM process.