Additive manufacturing of weft knitted and braided fabric structures with fused deposition modeling

Additive manufacturing (AM), also commonly called three-dimensional (3D) printing, allows fabrication of complex objects within a limited time frame with minimal waste production. The purpose of this research is to design, 3D print, and analyze the mechanical properties of fabric structures. Two different fabric types are considered for this work: weft knit fabric and braided fabric structures. A single yarn and weft knitted fabric structure were designed, fabricated and weft knitted fabrics are tested. Different designs of braided structures such as diamond braid, regular braid, Hercules braid, triaxial braid, and bi-furcated braid are designed, fabricated, and tested. Poly(lactic) acid (PLA) filaments were used to print the fabric structures. Mechanical properties and morphological structures were studied using the printed structures. The results showed that weft knitted fabrics possess a good ductile response before failure showing a tensile displacement in the range of 12-15 mm, and the peak force exhibited is nearly 250 N. On the other hand, the maximum flexural displacement is approximately 10 mm, and the load is in the range of 15-22 N in the wale direction, and 85-95 N in the course direction. Braided structures showed that they can bear significant amount of compressive load having displacement at failure of more than 25 mm. Optical microscope (OM) analysis showed that the yarns contain voids and cracks that contributed to the failure of the samples. The additively manufactured weft knitted fabric structures can be used in wearable, filtration, and geotextiles applications whereas the circular braided structures can be used in shock absorption applications.