Electric fields and local heating in additively manufactured nanocomposite parts

Conventional methods of thermoplastic manufacture suffer from high capital costs, while fused deposition modeling (FDM) faces the challenge of poor adhesion between printed layers. We have previously shown that carbon nanotubes can be used as electric field susceptors to locally heat the interfaces between printed layers. We also showed that dielectric barrier discharge (DBD) plasma applicators mounted on FDM nozzles can pass current to printed parts for welding. Little is known, however, about the interaction between the electric field and the printed part. In this work, we simulate the internal heating behavior of printed parts with local variations in conductivity. These studies show that thermal penetration scales with conductive surface layer thickness; the results also indicate that conductive inclusions within parts can create hotspots. These findings explain the heating behavior of FDM printed parts when coupled to a DBD applicator and show that inclusions within the parts could create mechanical defects.