Comparison of Scan Strategies for Side Roughness Optimization of Al6061-Zr Alloy Produced by Laser Powder Bed Fusion (L-PBF), Benefits and Drawbacks on Different Part Profiles

Abstract

Laser Powder Bed Fusion (L-PBF) is an additive manufacturing process that allows to build parts by solidifying powder bed, layer by layer, with a laser. This approach offers the possibility to build complex geometries. However, due to the succession of layers, the use of powder as raw material and melt pool dynamic, the surface roughness generated through this process is a limitation for some applications. Several works have been conducted to improve surface roughness by improving scan strategies such as contouring, and compensation optimization. However, these improvements are mostly applied on usual materials and on simple geometries. The aim of this work was i) to compare roughness obtained on cubes with high performance aluminium alloy (6061-Zr) and cast alloy (AlSi7Mg), ii) apply roughness optimization strategy on 6061-Zr on cubes and iii) compare typical L-PBF geometries obtained with and without roughness optimization strategies. This study shows that LPBF using Al6061-Zr alloy produces a higher roughness than AlSi7Mg (+16 %). The strategies used allowed the roughness to be reduced (-63 %) as well as obtaining a better circularity and a more homogeneous surface. It was also shown that some strategies have weaknesses for specific geometrical shapes.