SMC成形品の欠陥に及ぼすリブ非対称性の影響

抄録

The SMC has been developed as a material for the mass production system using press moulding, but some problems arise due to its heterogeneity caused by fibre orientation. The faults observed in the products, such as the appearance of brittle regions in the resin-rich parts or at the weld lines and the surface sink produced at the convex parts, may be regarded as the moulding problems.
The purpose of this study was to prevent the above troubles and to construct the CAD system for SMC press moulding process. The case of the symmetrical configuration with one rib part in full charge was treated in the previous paper. In this paper, the effect of asymmetrical configuration with one or two rib parts was investigated to solve the above problems associated with the flow state through the evaluation of flexural strength determined after observation of the material flow state. The analytical method was established by using a linear incremental finite element method and considering the fibre orientation and heterogenity.
It was found that the tendency to go around the rib corner increased with increasing the degree of asymmetry, resulting in the resin rich region at the rib corner and no surface sink. Although the weld line at the opposite side of the rib remained, the reduction of flexural strength became less due to curving of the weld line. The stress analysis after the observation of the flow state supports the above tendency well.