Mold Fill Time and Void Reduction in Resin Transfer Molding Achieved by Articulated Tooling

Tool articulation is proposed as a means to improve mold fill time and to reduce void generation in resin transfer molding (RTM). Following a brief review of conventional RTM and a discussion of the limitations on the factors that control fluid flow through porous media, the articulated tool concept is described. The sequence of motion of an articulated segmented mold necessary for consolidation, void removal and accelerated fluid flow through a fibrous preform is described. An analysis of the process using a fiber preform with orthotropic permeability is outlined from which mold fill time is obtained. This is compared with conventional RTM mold fill times using typical resin properties and fiber volume fractions. In addition, void reduction in the articulated process relative to conventional RTM is investigated. For the conservative assumptions used in the analysis, the articulated process demonstrates an improvement by a factor of at least five in mold fill time compared with conventional RTM, accompanied by reduced void generation.