Development of CAE system in BMC compression modeling - prediction of deformation in material at curing process

摘要

Recently BMC (Bulk Molding Compound) compression molding has been applied in the manufacturing of high-grade bath-tub. BMC is thermosetting resin and its compression molding has mass production capability. In compression molding, heat cracks often arise at comer, which are molding defects. It has not been clearly the accurate generating factor of heat cracks in the BMC compression molding. Nowadays, heat cracks are suppressed by manufacturer's experiences or trial and error. The purpose of this paper is to study the generating factor of beat cracks induced cure shrinkage in phase transformation by developing the numerical analysis of curing process. At first, we experimented with L-shaped specimens, by changing mold temperature and thickness. Next, to numerically observe non-uniformity in the material, we carried out two-dimensional heat transfer and thermoelastic analysis. Consequently, we got good agreement of heat cracks initiation position observed experimentally and generating position of the local strain obtained analytically. It was found that cracks arose in the case cure shrinkage restricted by cured outer material at finally cured position.