Novel non-destructive inspection techniques for laser powder deposition inspection

Abstract

A novel non-destructive testing (NDT) techniques for inspection of parts and components manufactured by Additive Manufacturing Processes (AMP), in particular Laser Metal Deposition (LMD), has been developed. LMD is a technology that has been maturing over the last 20 years and has found application in repair, coatings, hybrid build and 3D near net shape manufacture of small intricate parts that can be used in aero and automobile engines to improve efficiency. Currently this technology cannot be used to supply some of these parts because absence of flaws, which might be left in the component during manufacture, cannot be guaranteed. Today, quality is assessed by sample destructive testing, which gives slow feedback and is expensive. Some form of non-contact NDT would be the desired solution so that parts can be made right first time and with reduced cost, accordingly we used laser source and receiver to inspect samples for defects. The best scheme consists in linking the NDT device to the LMD nozzle and check the absence of flaws of the deposition soon after its production. The selected configuration is easy to be implemented and ideal for detecting surface-breaking defects, since it permits Rayleigh waves to be used in the inspection, and it is also useful for time-of-flight measurements of the ultrasound diffracted by volumetric defects. Both experiments and numerical simulations will be presented.