Experimental study of laser powder bed fusion (L-PBF) gas shield inlet optimization and its effects on part quality.

Costes, Mathilde; Arnaud, Lionel; Lefebvre, Philippe; Mandou, Quentin

In laser powder bed fusion (L-PBF) manufacturing, inert gas flow aids in removing spatters and fumes generated during laser-material interaction, ensuring quality of fusion and consequently, the quality of the manufactured parts. This study examines gas flow homogeneity's impact on part quality across the build plate. To do this, gas velocity mappings near the manufacturing plate (XY plane) and at four heights (Z-axis) were performed on a Renishaw AM400 machine using a Pitot tube and a hot-wire anemometer. Four gas inlet configurations are compared to maximize the permissible velocity at the build plate level (1 to 2 m/s) with the constrain of preventing the powder bed from being blown away. AlSi10Mg aluminum sample density measurements served as performance indicators, to quantify the effect of gas flow variations, taking into account their positions within the manufacturing bed. High-speed camera observations and numerical simulations supplemented the analysis. Results indicate gas flow inlet arrangement significantly influences flow homogeneity, reducing non-uniformity by almost 40%. Porosity is also reduced by around 20% and porosity variations on the build plate are reduced by more than 25%. Sample density increases primarily at the plate center and farthest from the gas inlet. Areas closest to the inlet show no significant density change compared to the standard configuration.

GAS flow; SHIELDING gases; NOBLE gases; INLETS; POROSITY

International Journal of Advanced Manufacturing Technology, 2024, Vol 133, Issue 11/12, p5299

0268-3768

Academic Journal

10.1007/s00170-024-14035-3