Effect of surface state and material on surface quality enhancement by Dual Laser Powder Bed Fusion

Parts produced by Laser Powder Bed Fusion typically exhibit a limited surface quality often requiring systematic post-processing. The KU Leuven AM team recently developed a Dual Laser Powder Bed Fusion strategy to improve the quality of inclined up-facing surfaces during building. It consists of two steps: (1) a pulsed laser induces shock waves to remove powder from inclined surfaces, followed by (2) in-situ laser remelting of the newly exposed surfaces. The first part of this paper covers the powder removal efficiency using shock waves depending on the used material. A design of experiments was performed for horizontal samples of tool steels, titanium and aluminium alloys. The second part deals with the effect of the initial surface state on the powder removal efficiency for inclined surfaces (SaR,LT60=16.2 µm, SaR,LT120=24.0 µm). Finally, the third part demonstrates the surface quality improvement, resulting in a reduction of Ra up to 61% for 15° inclinations.Mechanical Engineerin

Improving fatigue performance of metal parts with up-facing inclined surfaces produced by laser powder bed fusion and in-situ laser remelting

status: Published onlin