The increasing implementation of additively manufactured parts into safety-critical applications is accelerating the demand for non-destructive evaluation as a means of quality control for defect detection during the build process. Identification of a critical defect in the part before its completion can enable early termination of the build, resulting in both reduced material costs and machine time. Additionally, current post-build inspection techniques have limited resolution capability as the size of the manufactured part increases.
An adaptation of Acoustic Wavenumber Spectroscopy technology was implemented into a laser powder bed fusion machine to perform in-situ direct-part measurements and provide a three-dimensional inspection volume of the entire build. The processing of data for each layer is quick enough to be performed during the lasing of the subsequent layer, enabling the potential for early termination of the build when critical defects are identified.
Various processing techniques were used to detect changes in the steady-state ultrasonic response that indicate different defect types. The data analyses used to identify regions of defects based on the response data are presented. This work ultimately demonstrates a practical means for in-situ monitoring of additive manufacturing parts to ensure quality control for safety-critical applications.