Lifecycle Digital Twins for Photopolymer Products: Material State, Process History, Service Updating and Prediction

A digital twin is useful only if its virtual state remains meaningfully connected to the physical system. Photopolymer products pass through multiple irreversible or partly reversible states: liquid formulation, exposed green body, washed part, dried part, post-cured network and service-aged article. A model that collapses these stages into one material identifier is not a lifecycle twin. This review defines a state-transition architecture that binds formulation identity, machine history, process measurements, post-processing and service observations to versioned models. It distinguishes a static digital model, a one-way digital shadow and a bidirectionally updated twin; addresses uncertainty and model drift; and specifies requalification triggers when physical state or model structure changes. Current digital-twin literature and additive-manufacturing demonstrations support the architecture, but direct lifecycle twin validation for photopolymer products remains limited. ER-409.