EUROPEAN CONGRESS AND EXHIBITION ON ADVANCED MATERIALS AND PROCESSES - EUROMAT 2021

Prototyping alternatives for Powder Injection Moulding (PIM) components involving additive manufacturing have been studied in the recent years. Fused Filament Fabrication (FFF), which is an indirect and sinter-based printing technology, is selected for this study, since it is the most cost-effective solution that leads to similar PIM microstructures and performance of the sintered parts. Furthermore, this PIM prototyping strategy becomes more attractive when POM-based filaments are involved, allowing the direct industrial transference of the feedstock into the European companies. An in-house POM-based binder has been developed for both PIM and FFF processes and a suitable catalytic debinding was confirmed with this hybrid feedstock. The feedstock was fabricated by mixing 57 vol.% of Fe-8Ni alloy with the binder and a rheological study was undertaken to predict its processability. In addition, the mechanical behaviour of the filament was explored, regarding the tensile strength properties. Then, a complete optimization of the printing stage to achieve high quality green parts shaping was investigated, in terms of bed configurations, printing temperature, layer height and printing speed, among others. Finally, sintered parts were characterized (adhesion and diffusion between layers, alloy microstructure, density, microhardness, shrinkage, etc) confirming that the so-called hybrid POM-based feedstock is suitable for both catalytic FFF and PIM processing technologies.