MODEL FOR DETERMINING THE VENT LOCATIONS AND THE FILL TIME OF RESIN TRANSFER MOLDS

Simple models were developed for determining the vent locations and the fill time of resin transfer molds containing thin flat preforms with isotropic permeabilities. The in-plane shape of the preform is arbitrary and the preform may contain impermeable inserts. The vent locations required to avoid trapping air bubbles are determined by geometric considerations. The time required to fill the mold is calculated by treating the resin flow inside the mold as partly radial and partly channel-like flow. Tests were performed with different shape molds with and without inserts. The vent locations required to avoid air bubbles and the time required to fill the mold were determined. The experimentally established vent locations were in good agreement with the vent locations given by the model. The measured and calculated hh times also agreed well.