Evaluation of Preform-Mold Fit in Resin Transfer Molding

A major concern in Resin Transfer Molding is race-tracking whereby the matrix flows around the preform and arrives at the vents prematurely. Race-tracking, which is usually caused by a preform-mold misfit, could cause an entire part to be scrapped since recovery from a non-fill is not possible for these thermoset composites. The mold-preform-fit is evaluated by correlating the flow characteristics of nitrogen gas introduced into the ready-to-inject mold with the nature of the skewness of the actual resin flow front. The technique enables us to evaluate the process setup and to determine whether to inject the resin or to re-work the preform-mold fit before the resin injection process.