Advancing Tomographic Volumetric Printing Via Oxygen Inhibition Control: Improved Accuracy and Large-Volume Capability.

Tomographic volumetric additive manufacturing (TVAM) is an emerging 3D printing technology capable of producing complex structures in seconds. However, achieving reliable prints using TVAM requires sufficient light penetration throughout the print volume, which often limits the photoinitiator (PI) concentration that can be used. In (meth)acrylate-based photoresins, this constraint severely restricts achievable print size and quality due to oxygen inhibition. To address this challenge, a chemical strategy is demonstrated to control the oxygen inhibition period without compromising light penetration, using an amine, a thiol, and a phosphine additive as representative examples. Among these, N-methyldiethanolamine (MDEA) emerged as the most promising candidate, effectively reacting with non-reactive peroxy radicals to regenerate propagating radicals and sustain polymerization. Incorporating MDEA into a low-PI photoresin enabled high-resolution and large-volume printing in a custom-built TVAM system, achieving a root-mean-square surface deviation of 0.175 mm (≈2 pixels) and printable structure sizes up to 60 mm. These advances represent a 16-fold increase in print volume relative to the previous TVAM demonstrations and enable high-throughput fabrication of multiple complex parts without sacrificing print quality. This work establishes a scalable approach to overcoming oxygen inhibition in (meth)acrylate TVAM systems, unlocking new possibilities for large-volume, high-resolution additive manufacturing.