Abstract Laser powder bed fusion currently finds applications in a variety of engineering fields. However, the high upfront cost can be a barrier to the wide utilisation of this additive manufacturing technology, due partly to the high cost of the feedstock material. This can be mitigated by the reuse of unmelted feedstock powder recovered at the end of the manufacturing process, and as such, this research investigates the influence of AlSi7Mg powder reuse during laser powder bed fusion. Over ten build cycles, it was found that spatter production and the preferential consumption of fine particles increased the average particle size with the D90 value seeing the largest increase, while improvements in powder flowability were also observed. No microstructural changes occurred due to powder reuse; however, the oxygen content in the manufactured parts doubled while there was a 7.8% reduction in magnesium content. Tensile, flexural, and impact toughness values all saw minimal changes, with failure occurring along melt pool boundaries or at surface defects created by the removal of support material. Overall, part orientation had a greater impact on mechanical properties than powder reuse. Overall, these results show that although changes to a powder batch may occur due to powder reuse, this does not necessarily change the mechanical performance of the built parts. Powder reuse of AlSi7Mg is therefore an industrial solution to decrease cost and waste.
Warner et al. (Thu,) studied this question.