AbstractFabrication of structures in unstructured environments is a promising field to expand the application spaces of additive manufacturing (AM). One potential application is to add new components directly onto existing structures. In this paper, we developed a versatile, reconfigurable direct ink write (DIW) manufacturing method in tandem with a two-stage hybrid ink designed to fabricate high-strength, self-supporting parts in unconventional printing spaces, such as underneath a build surface or horizontally. Our two-stage hybrid DIW ink combines a photopolymer and a tough epoxy resin. The photopolymer can be cured rapidly to enable layer-by-layer printing complex structures. It also possesses adequate adhesion to allow the fabrication of large volume structures on a diversity of substrates including acrylic, wood, glass, aluminum, and concrete. The epoxy component can be cured after 72 hours in ambient conditions with further increased adhesion strengths. We demonstrated the capabilities of the reconfigurable DIW extrusion nozzle method to print complex structures in inverted and horizontal environments. Finally, via the addition of DIW-deposited conductive paths, we created a functional 3D printed structure capable of in-situ deformation monitoring. This work has the potential to be used for applications such as appending new parts to existing structures for increasing functionality, repair, and structure health monitoring.Corresponding author: H. Jerry Qi, qih@me.gatech.edu
