IMMAFUSE

Additive manufacturing (AM) is a key technology that enables structures to be built by adding material layer by layer so as to obtain complex geometries that cannot be achieved with conventional machining techniques. AM represents a unique opportunity to optimize and lighten structures and thus reduce energy consumption. One of the processes widely used in the aerospace, energy, automotive or medical domains is the laser powder bed fusion (LPBF) process. Due to the complex physical phenomena involved in the laser-material interaction, instabilities in the melt pool morphology can affect the final quality of the structure. Defects that can occur during the process are: porosity, keyhole, ejecta, geometrical defects, surface defects, residual stresses, cracks, delamination, microstructural inhomogeneity. IMMAFUSE aims at developing an innovative instrumentation for the in-operando control of the LPBF process, enabling to capture the 3D morphology of the melt pool. A holographic system will be coupled to a LPBF machine and to a high-speed camera allowing to record holograms at the temporal and spatial scales of the LPBF process. The scientific objective is to be able to report on the efficiency of the digital holography system to study hydrodynamic phenomena in laser powder bed for different classes of materials which strongly differ in their thermo-physical properties (thermal conductivity, absorptivity or reflectivity). Structures of known geometries and industrial interest will be tested with in-operando diagnosis and preliminary analysis of the powder bed. A long-term objective of IMMAFUSE is to propose the compaction and the implementation on an industrial LPBF machine of a multimodal holography/X-ray tomography imaging for the control of repeatability and stability of the process. Eventually, this state-of-the-art tool could exalt the democratization of laser additive manufacturing in the industry.