Development of instrumentation for eddy current in-situ monitoring of Laser Powder Bed Fusion
Résumé
The Laser power bed fusion (L-PBF) additive manufacturing process is commonly used for fabrication of complex metal parts. To ensure the parts quality, monitoring of the manufacturing process by an instrument operating continuously during the manufacturing process should be carried out. The existing industrial solutions are limited in the sense that they are restricted to the detection of anomalies within machine state parameters or in the surface layers of the part under construction. Eddy current testing is a promising non-destructive testing method that could be applied for the layer-by-layer inspection of fused material during part fabrication. This inspection enables to follow the defects evaluation not only on the surface of the last fused layer but at the scale of the several fused layers. An eddy current sensor has been developed and adapted to perform measurements in a L-PBF machine during the manufacturing phase (in-situ). The performance and potential of the technique in terms of robust integration in the machine and defects evaluation have been studied. The obtained results allowed to evaluate the detection limits according to the width and the height of the defects during the manufacturing of the part. The influence of the powder presence around the fused area has also been studied.