C.B. Sweeney, M.J. Green, M.A. Saed
Texas A&M University,
United States
Keywords: 3D printing, additive manufacturing, composite, nanoocomposite
Summary:
Additive manufacturing through material extrusion (ME), often termed 3D printing, is a burgeoning method for manufacturing thermoplastic components. However, a key obstacle facing 3D-printed plastic parts in engineering applications is the weak weld between successive filament traces, which often leads to delamination and mechanical failure. This is the chief obstacle to the use of thermoplastic additive manufacturing. We have recently demonstrated a novel concept for welding 3D-printed thermoplastic interfaces using intense localized heating of carbon nanotubes (CNTs) by microwave irradiation. The microwave heating of the CNT-polymer composites are a function of CNT percolation, as shown through in situ infrared imaging and simulation. We apply CNT-loaded coatings to 3D printer filament; after printing, microwave irradiation is shown to improve the weld fracture strength by 275%. Recent results indicate that these fields can actually be mounted on the 3D printer head itself. These remarkable results open up entirely new design spaces for additive manufacturing and also yield new insight into the coupling between dielectric properties and electromagnetic field responses for nano-filled materials. Further study has shown that low-frequency RF fields can also couple with CNT networks, allowing for a variety of rapid scanning techniques without any need for shielding. We have demonstrated that such techniques can be used to induce rapid localized heating in a range of technologies, including thermoset 3D printing and localized thermoset curing, with applications to the automotive sector.2