A State-Resolved Framework for Industrial Additive-Manufacturing Technology Selection Across Polymers, Metals, Ceramics and Advanced Materials

Industrial additive manufacturing spans seven standard process categories and a growing set of adjacent, non-layerwise, direct, indirect and hybrid implementations. Category names alone do not identify the state of the object leaving the machine, the transformations needed to obtain a usable component or the factory evidence required for repeatable production. This qualitative engineering review develops a state-resolved framework for screening additive-manufacturing routes across polymers, metals, ceramics and advanced materials. It separates feedstock state, shape-creation mechanism, usable scale and orientation, support or depowdering strategy, as-built state, mandatory post-processing, delivered material state and intended-use qualification. The seven categories are mapped together with exposure-architecture, indirect-tooling, functional-material and adjacent solid-state-deposition overlays. The comparison addresses geometry, throughput, material utilisation, labour, safety, surface state, anisotropy, shrinkage, inspection and economics without assigning universal scores. Representative primary studies show why raster direction, powder history, exposure architecture, droplet waveform, melt-pool regime, green-body processing, particle impact, thermomechanical deposition, thermal history and support environment remain route-specific. The decision gate begins with the required delivered state and works backward through the complete process chain. A worked ceramic example shows how the framework records candidate routes, invalidation gates, evidence gaps, provisional survivors and no-go rationale. The framework supports route screening, experimental planning and qualification design; it does not replace application-specific costing, process validation, regulatory assessment or production-site qualification.