Influence of process parameters on microscopic morphology and mechanical properties of 3D printed continuous carbon fiber reinforced polyamide6 composites

High-performance continuous fiber prepreg filament has become a research hotspot in the field of additive manufacturing in recent years, and it is considered as an effective choice to improve the mechanical strength of thermoplastic composite printed parts. However, the weak interlayer bonding and porosity brought by layer-by-layer printing affect the strength of the printed parts. In this paper, the microscopic morphology and mechanical properties of continuous carbon fiber reinforced PA6 composites prepared under different process parameters were investigated and explored the relationship between process parameters on resin-fiber interactions. The results show that when the printing temperature is 260°C, the printing layer thickness is 0.2 mm, and the printing speed is 6 mm/s, the specimens show optimal mechanical properties, but the too-low layer thickness leads to localized heat accumulation and tiny defects, microscopically, the internal porosity and surface roughness increased; When the thickness of the printed layer is changed to 0.3mm, the specimen shows excellent mechanical properties. Microscopically, the resin is fully infiltrated between the fibers, the interlayer bonding is tighter, and the surface roughness and internal porosity are significantly reduced. Adjustment of process parameters can effectively enhance mechanical properties and improve interlayer structure.