Tough, Additively Manufactured Structures Fabricated with Dual-Thermoplastic Filaments

Fused filament fabrication (FFF) is the most common additive manufacturing technology, but parts fabricated using FFF lack sufficient mechanical integrity for most engineering applications. Herein, a dual material (DM) filament comprising acrylonitrile butadiene styrene (ABS) with a star-shaped polycarbonate (PC) core is fabricated using a novel thermal draw process. This DM filament is then used as feedstock in a conventional FFF printer to create 3D solid bodies with a composite ABS/PC meso-structure. Subjecting these parts to annealing temperatures intermediate between the glass-transition temperatures of ABS and PC produces a solid body with ductility comparable to injection-molded ABS and fracture toughness values 15 x higher than comparable as-printed ABS structures. The PC skeleton of specimens fabricated using the DM filament resists creep and polymer relaxation to maintain accurate part geometry during annealing. This novel DM filament can revolutionize additive manufacturing allowing low-cost printers to produce parts with mechanical properties competitive with injection-molded plastics.