3D printed bioactive and antibacterial silicate glass-ceramic scaffold by fused filament fabrication.

The fused filament fabrication (FFF) technique was applied for the first time to fabricate novel 3D printed silicate bioactive and antibacterial Ag-doped glass-ceramic (Ag-BG) scaffolds. A novel filament consisting primarily of polyolefin and Ag-BG micro-sized particles was developed and its thermal properties characterized by thermogravimetric analysis (TGA) to define the optimum heat treatment with minimal macrostructural deformation during thermal debinding and sintering. Structural characteristics of the Ag-BG scaffolds were evaluated from macro- to nanoscale using microscopic and spectroscopic techniques. The compressive strength of the Ag-BG scaffolds was found to be in the range of cancellous bone. Bioactivity of the 3D printed Ag-BG scaffolds was evaluated in vitro through immersion in simulated body fluid (SBF) and correlated to the formation of an apatite-like phase. Methicillin-resistant Staphylococcus aureus (MRSA) inoculated with the Ag-BG scaffolds exhibited a significant decrease in viability underscoring a potent anti-MRSA effect. This study demonstrates the potential of the FFF technique for the fabrication of bioactive 3D silicate scaffolds with promising characteristics for orthopedic applications.

Utilizing Fused Filament Fabrication for Printing Iron Cores for Electrical Devices.

This work details a polyolefin-elastomer-based binder system to prepare fused filament fabrication (FFF) filaments and print cores for coils for electrical engines. The processability, homogeneity, and thermal properties of the polyolefin-elastomer-based filaments are explored. A two-step debinding and sintering process was established for manufacturing dense iron parts. Results indicate the developed filaments possess superior printing and sintering (at 900°C) performance, yielding only 20% weight loss by polymer decomposition and 14 vol.% shrinkage. This indicates that the FFF technique potentially enables printing of innovative electric motor designs. The designed FFF filaments could be loaded with 80 wt.% Fe powder while keeping a decent melt-viscosity for the printing process. Due to the high metal loading, dense iron parts could be sintered without bending or deformation.