Effects of fabrication parameters on the mechanical properties of short basalt-fiber-reinforced thermoplastic composites for fused deposition modeling-based 3D printing

This study develops sustainable and recyclable basalt fiber (BF)-reinforced flexible plastic low-temperature polyamide (L-PA) filaments for fused deposition modeling (FDM)-3D printing and optimizes fabrication parameters to achieve eco-friendliness, high mechanical performance, and lightweight FDM-fabricated composite parts. Herein, 15 wt% fiber-filled composite filaments were prepared by an extrusion process. Three manufacturing parameters, including printing temperature, printing speed, and layer height, were investigated for their effects on the tensile and compression properties through Taguchi L9 orthogonal experiments. To obtain a suitable printing temperature range, the thermal behaviors of the composite filaments were characterized by differential scanning calorimetry, thermogravimetric analysis, and melt flow factor measurements. In addition, the FDM-printed specimen surface and tensile fracture interface after tensile tests were observed and analyzed by SEM. Results show that the printing temperature has the greatest effect on the mechanical properties of the BF/L-PA composites, followed by the layer height, whereas the printing speed has the least effect. This indicates that better mechanical properties can be obtained at higher printing temperatures and lower layer heights. Compared with neat L-PA, adding BF to L-PA improves the tensile modulus, tensile strength, and specific energy absorption per volume without sacrificing ductility, showing the maximal increases of 176.6%, 142.0%, and 172.2%, respectively, as compared with neat L-PA. A SEM micrograph reveals that the primary factors for these improvements are the fibers acting as reinforcement filling in the L-PA matrix and the good bonding properties between the adjacent infills in a single layer and among successive layers.