IDENTIFICATION OF SUB SURFACE DEFECTS IN PARTS PRODUCED BY ADDITIVE MANUFACTURING, USING LASER GENERATED ULTRASOUND
Additive manufacturing (AM) offers a number of benefits over manufacture by conventional means, giving an increased design freedom and the opportunity to integrate multiple components, saving weight. The rigorous standard for material integrity set by the Aerospace and Medical sectors necessitates the development of systems to ensure the quality of AM components is sufficient. Laser ultrasonic testing (LU) is a non contact inspection technique which might be well suited for in situ monitoring of AM processes, as measurements can be taken on curved surfaces and at elevated temperatures. In this paper, the results of a recent study looking to generate and identify sub surface defects in samples produced by laser powder bed fusion are shared. Samples with defects replicating those commonly resulting from processing by AM have been seeded and analysed post process, in order to establish the limits of detection for LU and to assess the suitability of this technique for in situ inspection of AM.