Microwave Radiation in Volumetric Additive Manufacturing to Create 3D Ceramics

Additive manufacturing has come a long way in the past 20 years to create complex 3D architecture that are hard to produce using traditional manufacturing methods. Many advances in the last 10 years have focused on expediting the time to create the 3D objects to rival methods aimed at industrial or large-scale production. One printing method of interest is volumetric additive manufacturing (VAM) using optical light, which can print a single object in one projection. However, VAM is unable to process resins that are opaque or have high loadings of powder. Our team has devised a strategy to overcome these limitations through microwave curing of ceramic binder mixtures to produce 3D ceramic objects. The microwave radiation thermally cures the epoxide-based binder in place to create 3D ceramic green body, and sintering the object forms the ceramic part. Current efforts in the materials side of the project revolve around identifying how the initiator concentration and the loading of the silicon nitride powder in the binder influences the exothermic reaction to enable the localization of the cured spot within the ceramic binder mixture, and identifying how the binder is removed during the post-processing sintering to form a solid ceramic object. Current investigations have shown successful cure of highly loaded (~50% v/v) ceramic/binder mixtures, and the binder is successfully removed in the post-processing thermal treatment.