Spatially resolved acoustic spectroscopy towards online inspection of additive manufacturing

摘要

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