Simulation of Compression Effect on Filling Process in Compression Resin Transfer Molding

The compression resin transfer molding (CRTM) filling process involves two stages: the injection phase and the compression phase. Two injection modes are considered - constant volumetric flow rate and constant pressure-while the constant compression velocity is utilized in this study. Three typical cases are used to investigate the compression initiation effects on the filling process. When the inlet condition is a constant flow rate, the numerical results show that the compression has both increase and decrease effects on the inlet pressure. Thus, a discontinuity in the inlet pressure is present at the onset or the end of compression. Among three CRTM cases, the process with a simultaneous injection and compression end maximally reduces the inlet pressure by 80% but increases the mold filling time by 65% compared with the resin transfer molding (RTM). For the inlet condition being a constant pressure, the resin may flow out of the mold cavity through the inlet when an excessively low injection pressure and high compression speed are applied concurrently. Compared with RTM, the CRTM processes reduce the mold filling time by 68-76% but cannot ensure a reduction in inlet pressure. (C) Koninklijke Brill NV, Leiden, 2011