A challenge in extrusion‐based additive manufacturing of polypropylene (PP) filled with spherical particles is the combination of decent processability, excellent warpage control, and the retention of the tensile strength of neat PP. This study addresses this issue by adopting two approaches. Firstly, different size fractions of borosilicate glass spheres incorporated into PP are compared. Secondly, the temperature of the printing chamber (TCh) is varied. The effects of these features on the thermal, crystalline, morphological, tensile, impact, and warpage properties of 3D‐printed parts are examined. Smaller glass spheres (<12 µm) are found to be superior to larger fractions in all investigated aspects. Notably, the corresponding composites show higher tensile strengths than neat PP. An increase in TCh results in a more homogeneous temperature distribution within the printing chamber and promotes annealing during printing. Consequently, the dimensional accuracy of printed parts is improved. Additionally, β‐crystals and larger spherulites are formed at a higher TCh.

Due to a lack of long-term experience with burgeoning material extrusion-based additive manufacturing technology, also known as fused filament fabrication (FFF), considerable amounts of expensive material will continue to be wasted until a defect-free 3D-printed component can be finalized. In order to lead this advanced manufacturing technique toward cleaner production and to save costs, this study addresses the ability to remanufacture a wide range of commercially available filaments. Most of them either tend to degrade by chain scission or crosslinking. Only polypropylene (PP)-based filaments appear to be particularly thermally stable and therefore suitable for multiple remanufacturing sequences. As the extrusion step exerts the largest influence on the material in terms of temperature and shear load, this study focused on the morphological, rheological, thermal, processing, tensile, and impact properties of a promising PP composite in the course of multiple consecutive extrusions as well as the impact of additional heat stabilizers. Even after 15 consecutive filament extrusions, the stabilized additively manufactured PP composite revealed an unaltered morphology and therefore the same tensile and impact strength as the initial material. As the viscosity of the material of the 15th extrusion was nearly identical to that of the 1st extrusion sequence, the processability both in terms of extrusion and FFF was outstanding, despite the tremendous amount of shear and thermal stress that was undergone. The present work provides key insights into one possible step toward more sustainable production through FFF.

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