Spatially Resolved Acoustic Spectroscopy Towards Online Inspection of Additive Manufacturing

Abstract

High-integrity engineering applications such as aerospace will not permit the incorporation of components containing any structural defects. The current generation of additive manufacturing platforms yield components with relatively high levels of defects. The in-line inspection of the components built using additive can provide closed-loop feedback and vary build parameters during fabrication to minimise such defects. This article reviews the capability of spatially resolved acoustic spectroscopy to be used as an in-line inspection tool for detecting the changes in parts induced due to variations in build parameters. The first considers the build laser power and the second varies the laser scan strategy used to build the component. Using the detected probe light intensity map and the measured surface acoustic velocity, the detection of surface defects, subsurface defects and component microstructure can be measured.