Simulations of cyclic, transient variations of mold temperatures in the SMC compression molding process

The dual reciprocity boundary element technique is used to simulate the cyclic SMC compression molding process, taking into account the heat transfer within the whole mold. The cyclic, transient variations in mold temperatures at different mold locations are illustrated through the analysis of a plate mold. The transient temperature fluctuation near the mold cavity surface is much larger than that away from it. It was also found that owing to the high heating fluid temperature (compared with the ambient air temperature), the heat transfer at the mold exterior surface shows a significant effect on the mold temperature distribution, especially when the mold is a small or medium size. The present method provides a complete and more accurate description of the mold temperature variation during the whole cycle history by including the mold as the analysis domain, meanwhile minimizing the computation time. Other analysis methods, including the constant mold wall temperature approach, the hybrid shape-factor/finite element method, as well as the cycle-averaged boundary element technique imposed with 1-D transient analysis, basically overestimate mold wall temperatures and the associated charge conversion rate.