Unstructured Direct Ink Write 3D Printing of Functional Structures with Ambient Temperature Curing Dual‐Network Thermoset Ink

Abstract

Fabrication 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. Herein, a versatile, reconfigurable direct ink writing (DIW) manufacturing method is developed 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. This two‐stage hybrid DIW ink combines a photopolymer and a tough epoxy resin. The photopolymer can cure rapidly to enable layer‐by‐layer printing of 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 cure after 72 h in ambient conditions with further increased adhesion strengths. The capabilities of the reconfigurable DIW extrusion nozzle method to print complex structures in inverted and horizontal environments are demonstrated. Finally, via addition of DIW‐deposited conductive paths, a functional 3D‐printed structure capable of in situ deformation monitoring is created. 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.