A series of systems that uses specially designed nondestructive testing techniques for rapid in-line inspection of laser-powder-deposited layers has important implications for the aerospace and automotive sectors; for example, where validation of components made using additive manufacturing techniques has until now been difficult to achieve.

The systems, developed under the EU-funded research project INTRAPID, uses laser ultrasonics, laser thermography and eddy current testing techniques, because each of these has a small inspection footprint – necessary to inspect a thin deposited layer. The systems comprise newly built specialist equipment as well as a software suite, which includes data acquisition, display and analysis.

To determine inspection performance, the researchers produced a wide range of reference samples in different materials and of varied shape containing machined flaws. They also devised techniques to introduce known flaws in deposited layers of either Inconel 600 or a copper alloy on aluminum substrates. Subsequent testing of these samples enabled the team to produce performance data for each inspection method, as a graph comparing flaw size against its depth below surface.

The investigators successfully demonstrated that inspection can follow the deposition process by means of a simple translation of robot movement.

One system is expected to be used first by the automotive industry in the production of a new generation of laser-additive-manufactured components.

INTRAPID was coordinated in the UK by TWI; project partners include Bytest of Italy, Tecnitest of Spain, Polkom of Poland, LPW Technology of England, Toyota of Belgium, Kingston Computer Consultancy of the UK and UNIPA of Italy. The work was funded by the European Commission through the Research Executive Agency.