Composite Additive Manufacturing
Pushing the Boundaries of Composite Additive Manufacturing
Additive manufacturing (AM) is hailed for freedom in complex component design and low material waste. Originally conceived for thermoset based stereolithography, all classes of materials are now being exploited and produced in tandem with additive processes to push the possibilities of engineered structures. Excitingly suitable for this field are fiber reinforced thermoplastics, which can offer more sustainable and recyclable materials for multiscale components. We seek to improve the quality and printability of novel high volume fraction filaments, with both stiff and compliant continuous fiber reinforcement. Although fused deposition modeling of continuous fiber composites can offer uniquely reinforced structures, there is limited understanding on composite behavior and its dependence on the printing process mechanics. As such, filament strengths are evaluated at specific stages of printing under uniaxial tension and Weibull statistics are applied to characterize the strength distribution. To be implanted in industry, this system must meet the rigorous standards for reliable and predictable manufacturability. We intend to explore and overcome associated challenges of stiff continuous fiber printing to produce net-shape components with high strength, reliability, and throughput.
4 quad view of brightfield and dark field optical images of High Vf compliant filament for 3D printing.
An additional objective of this project is to develop a new class of composite filaments inspired by the biological structural materials of dermal armors, particularly fish scales, that enable 3D printing of advanced engineering structures with superior durability. Unlike traditional continuous fiber filaments, this filament will consist of an assembly of compliant fibers with extremely high toughness and a comparatively stiff outer matrix. It is hypothesized that through careful selection and treatment of both fiber and matrix components, successful chemical bonding between the fiber and matrix interface will exhibit decreased voids and increased final part strength. The volume fraction and size distribution of additives are expected to result in a gradient of stiffness, allowing for optimization of toughness and puncture resistance of the subsequent structures. The novel filament could provide a spectrum of mechanical properties (stiffness, strength, and toughness) that can be customized to fulfill the objectives of the printed part.
One area where polymer-based materials and composites are infrequently used is in marine environments. However, such materials may still fulfill many other demands of the application, and only a poor understanding of the durability of the material limits its usability. To that end, marine degradation studies are also performed on polymer parts produced by 3D printing.