Research on optimization of high efficiency additive manufacturing process of GF/PP thermoplastic composites

Thermoplastic composites are vital for automotive lightweightening, but traditional manufacturing faces cost and efficiency limitations. This study employed automated additive manufacturing (AM) with in situ consolidation to address these challenges for large components. The continuous glass fiber reinforced polypropylene (GF/PP) prepreg was used as the raw material, and the laminates were prepared by using the self-developed hot gas assisted AM platform. The response surface method was employed to investigate the influence of key process parameters including hot gas temperature, lay-up speed, roller pressure, and their synergistic effects on the interlaminar shear strength (ILSS). Results identify optimal parameters: hot gas temperature 376°C, roller pressure 0.28 MPa, lay-up speed 0.50 m/min. The ILSS achieved under these conditions is 24.4 MPa, representing 87.8% of the performance of compression molding samples, and the forming time of a single component is approximately 62.6% of the time required for molding. Ultrasonic C-scan and scanning electron microscope confirmed good and stable interlaminar bonding quality for AM parts under optimum parameters. The maximum error between actual ILSS and the response surface model prediction was 3.68%. This work provides a foundation for the low-cost, high-efficiency molding of thermoplastic composites.