Additive manufacturing metrology In-Situ Metrology for Metal Additive Manufacturing: Why Measurement Is Becoming the Qualification Bottleneck Updated: 13 September 2026 Short answer: Metal additive manufacturing can create complex parts layer by layer, but qualification remains difficult because manufacturers cannot rely only on the machine settings or a final visual inspection. NIST identifies the lack of reliable and validated in-situ measurements as a major barrier to wider adoption of metal AM. Current work focuses on measuring thermal behaviour, melt-pool activity, microstructure evolution, residual stress, powder-layer condition and defects during the build, then validating those measurements against controlled reference data and final part properties. Additive manufacturing changes one of the basic assumptions of conventional production. In machining, a manufacturer starts with material and removes it. In metal additive manufactur...