The majority of additively manufactured plastic parts built with powder bed fusion (PBF) processes are made of polyamide 12. Since only a fraction of powder ends up in the components built, part cake material and overflow powder has to be re-used for economic and ecologic reasons, even though its material properties are altered by thermo-mechanical stress during processing. Changes in bulk solid properties play a key role for the stability of the PBF process and the quality of manufactured parts. However, there is still no generally accepted method for the evaluation of used powders with respect to their processability and a lack of understanding of underlying bulk material mechanics. The aim of this study, exemplified for polyamide 12, is to assess widely applicable, standardized and process-adapted characterization methods in additive manufacturing and to shed light on the underlying phenomena causing the changes in flowability and packing properties of used powders.

大多数采用粉末床熔合（PBF）工艺制造的增材制造塑料零件均由聚酰胺12制成。由于只有一部分粉末最终填充在所制造的组件中，因此，为了经济和经济起见，必须重新使用部分蛋糕材料和溢粉。出于生态原因，即使其材料特性在加工过程中因热机械应力而改变。松散固体性质的变化对于PBF工艺的稳定性和制造零件的质量起着关键作用。然而，就其可加工性以及对底层散装材料力学的了解不足而言，仍没有一种普遍接受的方法来评估用过的粉末。这项研究的目的（以聚酰胺12为例）旨在评估广泛适用的材料，