EFFECT OF RIB ROOT SHAPE ON THE TENSILE STRENGTH OF PRESS AND INJECTION HYBRID MOLDED PRODUCTS MADE WITH CF/PA6 RANDOM PREPREG SHEET

The use of carbon fiber reinforced thermoplastic (CFRTP) contributes to weight reduction of automobiles and offers better gasoline mileage. Recently, to mold CFRTP with high-strength and highstiffness for complex shaped products with ribs and bosses, the hybrid molding system has been developed by combining press molding and injection molding. Although rib root shape is the important factor in the press and injection hybrid molding, the effect of rib root shape on the rib root strength has not been clarified yet. In this study, carbon fiber reinforced polyamide 6 composites were molded by press and injection hybrid molding. Rib root tensile test of T-shaped specimen cut out from the hybrid molded products and in-plain tensile test of the outer shell laminate were conducted to clarify the effect of rib root shape (radius of curvature R = 0 and 2.5). For rib root tensile test of T-shaped specimens, higher strength was obtained in the molded products with R = 0 than those with R = 2.5. On the other hand, in the case of in-plain tensile strength of outer shell laminate, higher tensile strength was obtained in the molded products with R = 2.5 than those with R = 0.