An Investigation of Printing Parameters of Independent Extrusion Type 3D Print Continuous Carbon Fiber-Reinforced PLA

Fused filament fabrication (FFF) technology is highly favored by various industries as the simplest and most commonly used technology in additive manufacturing. The embedding of continuous fiber-reinforced thermoplastic composites (CFRTC) is a great help to compensate for the mechanical properties of FFF-printed specimens. In this paper, the optimal printing parameters of printed specimens containing continuous carbon fiber-reinforced PLA were investigated by the Taguchi method, full factorial analysis, and the tensile test. Fiber printing layer thickness and fiber printing speed are significant factors. After excluding the influence of fiber overlap, the optimal printing parameters were obtained. When the thickness of the fiber printing layer is 0.05 mm, the speed of the fiber printing nozzle is 250 mm/min, and the temperature of the fiber printing nozzle is 210 °C, the maximum tensile stress of the sample is 189.52 MPa. In this paper, the maximum tensile stress of the specimen printed by different printing parameters can be doubled, which shows the influence of printing parameters on the mechanical properties of the specimen. Compared with the specimen using pure PLA printing, the increase was 703.5%. Then the failure mechanism of 3D-printed CFRTC specimens with different layer thicknesses was investigated by using microstructural morphology and tensile fracture interfacial property analysis. The influence of layer thickness parameters on the interfacial bonding force was revealed. Through analysis, it is found that the lower the thickness of the specimen printing layer, the better the interface bonding force of the specimen, and the minimum layer thickness suitable for FFF independent extrusion printer is found.