Resin Pool Effect on the Weld Strength of Injection Molded Carbon Fiber Reinforced Thermoplastics

Abstract

Effects of a resin pool on the weld strength of carbon fiber reinforced thermoplastics (CFRTP) were investigated using CFRTPs of different fiber lengths. Without the resin pool, the weld strength was unaffected by the fiber length, but a resin pool improved the weld strength. That improvement effect was found to depend on the distance from the merging point of two flow fronts entering into the resin pool. The CFRTP weld strength was determinedbytheinterfacial strength of the matrix and fiber, evaluated from the thermal residual strain and the tensile modulus of the matrix. Based on this mechanism, the weld strength improvement by a resin pool was explained by tilting of the fiber to the molding direction.