Printing of low-viscosity materials using tomographic additive manufacturing

Tomographic volumetric additive manufacturing (VAM) is a high-speed 3D printing technique that overcomes many of the challenges faced by conventional layer-by-layer based approaches. However, unlike other vat photopolymerization techniques, VAM must use much higher viscosity resins prohibiting the use of more commonly available lower-viscosity materials. Low-viscosity poly(ethylene glycol) diacrylate (PEGDA) has seen wide usage in bioprinting techniques but has eluded printing in VAM. Using a VAM printer with a high angular dose delivery rate, as well as tomographic projections optimized for low-viscosity printing conditions, we demonstrate high-fidelity VAM printing in PEGDA with viscosities as low as 12 cP. Micro-computed tomography imaging of printed parts reveal close-to voxel resolution limited performance. Furthermore, we have demonstrated the first direct printing of a low-viscosity hydrogel in VAM. The proposed method expands the viscosity range, and in turn the catalogue of materials accessible to VAM, giving this printing modality the broadest viscosity range of any vat photopolymerization technique.