Flaws encountered in metals additive manufacturing (AM) include lack of fusion and cracks occurring during solidification, stress relieving or due to unintentional stress raisers in the structure. These flaws may be difficult to detect using traditional NDT methods such as ultrasound scanning or dye penetrant due to the complex geometries involved, or may require characterisation techniques, such as X-ray CT, which are unsuitable for production environments due to high costs and protracted inspection times. Therefore, there is an industry requirement for an NDT method capable of rapid assessment of AM components. Non Linear Resonance (NLR) is a cost effective characterisation technique capable of providing a go/no-go rapid assessment of components. NLR has the advantage, over other linear resonance-based methods, of being a self-referencing technique, therefore capable of exposing flaws at early stages of manufacture without the need for a “known good” reference sample. This presentation will give examples of completed NLR systems and provide a summary of data collected for a variety of samples in a metal AM manufacturing lines, demonstrating the capability of the technique. In particular, it will focus on results obtained for thin-wall components, like heat exchangers, which would be impossible to test by other means.