Material Operating Windows in Tomographic Volumetric Additive Manufacturing: Gelation Criteria, Inhibition Reserve, Optical Transport and Exposure Drift
Segurola, Juan
2026-08-27 · Report · Version 1.1
Tomographic volumetric additive manufacturing forms a three-dimensional object by accumulating projected exposure throughout a resin volume. The geometry is reconstructed optically, but the decision to remain liquid, gel or become a recoverable green body is made by the material. This review treats tomographic VAM as a material-window problem rather than as a single threshold-dose problem. It distinguishes conversion onset, operational gelation and green-part recovery; defines the minimum target exposure, maximum background exposure and criterion-specific gel exposure needed to describe dose separation; and introduces normalised target margin, background reserve and combined exposure-window descriptors as reporting aids rather than standards. The framework then links these quantities to inhibitor and oxygen state, intensity-time history, absorption, scattering, refraction, rheology, sedimentation, thermal state, resin reuse and adaptive exposure control. Algorithmic correction and closed-loop feedback can reshape the delivered dose field or compensate for drift, but they do not replace formulation qualification or establish that a nominally identical resin state is stable. A minimum qualification matrix is proposed for resin identity, photochemical response, optical transport, reconstructed field, motion stability, green recovery, final conditioned properties, batch variation and uncertainty. Existing 3Dresyns volumetric-manufacturing documentation is treated only as implementation context. No current product label or successful print is interpreted as evidence of a universal gel threshold or transferable tomographic operating window.