High injection molding welding strength and cross-sectional analysis of carbon fiber composite materials

Abstract

Abstract In this study, carbon fibers, commonly used as reinforcement materials, were added to polyamide (nylon) PA6 to fabricate carbon fiber-reinforced thermoplastic composites (CFRTP), which were then subjected to injection molding welding. The aim of this research was to investigate the positive influence of carbon fibers on injection molding welding strength and explore the optimal injection conditions. Three different joining combinations and various injection parameters were examined. The tensile fracture surfaces after welding were observed using polarized microscopy and scanning electron microscopy. The reinforcing mechanism of carbon fibers was analyzed. Ultimately, the optimal conditions were determined as a mold temperature of 120°C, an injection temperature of 380°C, and an injection velocity of 150 mm/s. The addition of carbon fibers exhibited significant strengthening effects on the injection molded joints, and it also provided the potential for injection molding welding between resins with poor compatibility.