Spatially Resolved Acoustic Spectroscopy Towards Online Inspection of Additive Manufacturing

High-integrity engineering applications such as aerospace will not permit the incorporation of components containingany structural defects. The current generation of additive manufacturing (AM) platforms yield components with relativelyhigh levels of defects. The in-line inspection of components built using AM can provide closed-loop feedback and varybuild parameters during fabrication to minimise defects. This article reviews the capability of spatially resolved acousticspectroscopy (SRAS) to be used as an inspection tool for detecting defects and characterising microstructure in partsinduced by variations in build parameters. The authors first correlated changes to surface acoustic wave velocity and anincrease in defects to variations in build laser power, then identified changes to the component microstructure causedby variations in build laser scan strategy. This was carried out using the detected probe light intensity and the measuredsurface acoustic velocity