Mechanical Properties and Characterization of Polylactic Acid/Carbon Fiber Composite Fabricated by Fused Deposition Modeling

In this study, carbon fiber was reinforced in polylactic acid composites by fused deposition modeling to investigate the mechanical properties of polylactic acid/carbon fiber composites. Mechanical properties were analyzed by varying the layer thickness, raster angle, infill density and printing speed. Impact strength, tensile strength and flexural strength tests were carried to investigate the mechanical properties of composites. Design of experiments was carried by Box–Behnken design with 4 Factors and 27 runs. Mathematical models were developed to calculate the impact strength, tensile strength and flexural strength of PLA/carbon composites. The validity of the developed model was evaluated by analysis of variance technique. Scanning electron microscopy was employed to explore the mechanism of the fractured specimen. The tensile strength of the composites varied from 33.78 to 40.78 N/mm², flexural strength varied from 3.16 to 4.12 N/mm² and impact strength varied from 4.46 to 6.44 kJ/m². Tensile strength was primarily influenced by printing speed, while flexural strength and impact strength were predominantly influenced by raster angle and layer thickness, respectively. The fracture mechanism of composites specimens was influenced by voids, cracks, infill gaps and interface.