Development of highly filled nickel-polymer feedstock from recycled and biodegradable resources for low-cost material extrusion additive manufacturing of metals

Abstract

Material Extrusion Additive Manufacturing of Metals (sinter-based metal 3D printing) is the future of metal additive manufacturing as the technology is accessible, easy-to-use and affordable. This method typically starts by using high loading metal-polymer composites/filaments as the feedstock. The rheological behavior of composite affects the maximum metal content of the feedstock, and is influenced by type of components, filler shape and size distribution, as well as additives. In this study, highly filled metal-polymer filaments, with 75 wt% nickel content dispersed in polylactic acid (PLA) matrix have been made for the first time by using a simple single-screw extruder. Using biodegradable PLA alongside recycled nickel powders, which are produced by low-carbon-footprint Mond process, take steps towards affordability and sustainability considerations. Microstructure, rheological, mechanical, and thermal properties of feedstock filaments and 3D printed parts were evaluated. Printing parameters were also optimized, and the results showed that increasing the flow rate by 10 % enhances the overall quality of the printed part and reduces the gap between the 3D printed lines. The preliminary studies on debinding/sintering post heat treatments to get fully dense nickel parts also showed promising results using the developed methodology.