Effect of surface treatment on interface properties of carbon fiber reinforced <scp>PA6</scp> composites during overmolding

Abstract Carbon fiber‐reinforced thermoplastic composites have the advantages of lightweight and high strength and have broad application prospects in automotive lightweighting. This study uses the Overmolding process to mold carbon fiber‐reinforced nylon 6 composite materials. By using laser surface treatment and preheating technology, the interfacial bonding performance of the composite material is emphasized. By optimizing the embedding temperature, it was observed that the in‐plane shear strength increased by 13 times to 70 MPa, and the tensile strength increased by 10 times to 44 MPa. Similarly, by adjusting the melting temperature, the in‐plane shear strength was significantly improved, and the mechanical interlock and interfacial bonding were effectively enhanced by laser surface treatment, achieving the same effect as embedding preheating. By establishing a finite element model, the in‐plane tensile and in‐plane shear at the interface were accurately simulated, and the progressive failure process of the interface layer was successfully predicted. Highlights Laser energy density strengthens the overmolding interface. Optimizing insert, mold, and melt temperatures enhances interface bonding. Shear and tensile tests reveal differences in interface failure behavior. Finite element model accurately simulates overmolding interface failure. Laser treatment and temperature control are key to stronger interfaces.