Hybrid Metal/Polymer Filaments for Fused Filament Fabrication (FFF) to Print Metal Parts

Featured Application The development of hybrid metal/polymer filaments opens the possibility to expand metal 3D printing with investment costs accessible to small and medium enterprises. This will allow 3D printing of metal parts with the same approach used for desktop 3D printing, thus further democratizing the use of additive manufacturing in applications that cannot be fulfilled by polymeric 3D printing. The exploitation of mechanical properties and customization possibilities of 3D printed metal parts usually come at the cost of complex and expensive equipment. To address this issue, hybrid metal/polymer composite filaments have been studied allowing the printing of metal parts by using the standard Fused Filament Fabrication (FFF) approach. The resulting hybrid metal/polymer part, the so called green, can then be transformed into a dense metal part using debinding and sintering cycles. In this work, we investigated the manufacturing and characterization of green and sintered parts obtained by FFF of two commercial hybrid metal/polymer filaments, i.e., the Ultrafuse 316L by BASF and the 17-4 PH by Markforged. The Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray Spectrometry (EDS) analyses of the mesostructure highlighted incomplete raster bonding and voids like those observed in conventional FFF-printed polymeric structures despite the sintering cycle. A significant role in the tensile properties was played by the building orientation, with samples printed flatwise featuring the highest mechanical properties, though lower than those achievable with standard metal additive manufacturing techniques.

Automated summary

The development of hybrid metal/polymer filaments opens up affordable metal 3D printing for small and medium enterprises, allowing the printing of metal parts through the standard FFF approach and conversion into dense metal parts through debinding and sintering cycles. Building orientation played a significant role in the tensile properties of the parts.