Pre-contouring to improve the compatibility of Inconel939 with Laser Powder Bed Fusion
Researchers from IMDEA Materials Institute, Madrid, Spain and Industria de Turbopropulsores SAU, Bizkaia, have published a paper in Advanced Engineering Materials, that looks at the use of contour scanning to improve thin wall sections when Additive Manufacturing with Inconel 938.
The authors investigated the influence of adding a contour scan prior to hatching (precontouring) on samples produced by Laser Beam Powder Bed Fusion (PBF-LB). Walls with thicknesses ranging from 500 to 1500 μm, manufactured with two hatch scanning parameter sets that give rise to different microstructures and very high density in bulk samples of the same alloy, were investigated.
It was shown that, while the texture as well as the grain size and shape is only influenced moderately by the contour scanning strategy, precontouring does lead to a significant reduction of the melt pool depth. This effect becam increasingly pronounced with decreasing wall thickness.
‘Precontouring as a Tool to Improve the Laser Powder Bed Fusion Printability of Inconel939 Thin Walls’ highlights the role of the precontour scan as a heat sink, shifting the normalised enthalpy input toward lower values and thus limiting the accumulation of excess heat. The paper goes on to put forward pre-contouring as a scanning strategy to improve the manufacturability of thin sections.
The paper is available here.
