posted on 2020-03-05, 14:10authored byC. B. Sweeney, Matthew L. Burnette, Martin J. Pospisil, Smit A. Shah, Muhammad Anas, Blake R. Teipel, Bryan S. Zahner, David Staack, Micah J. Green
Material
extrusion (ME) 3D printing is a revolutionary technique
for manufacturing thermoplastic parts; however, the printed parts
typically suffer from poor interlayer bonding, which causes weak tensile
strength in the build direction. Many methods have been proposed to
address the mechanical deficiencies of 3D-printed parts, but most
fall short of a production-ready solution. Here we report the use
of a dielectric barrier discharge (DBD) plasma electrode mounted concentrically
around the nozzle of an ME 3D printer for in situ welding of thermoplastic parts. This is the first report of a DBD
being used as a non-contact means to induce Joule heating in resistive
composite materials. The polymer welding process is accomplished by
coupling the DBD with the carbon nanotube-loaded interfaces between
the 3D-printed layers. The current passing through the part results
in rapid resistive heating of the nanotubes and thermal welding of
the interfaces. We show that parts printed with this method have isotropic
strength and are equivalent to their injection-molded counterparts.