In order to bring down the cost of metal 3D printing, researchers and industrial R&D divisions are working on new approaches to the technology which forgo lasers and electron beams for other methods altogether. While XJet, in Israel, will be introducing its metal inkjetting to the world, hopefully, sometime soon, Northwester University scientists have their own metal inks which they say they can 3D print similarly to futilized filament fabrication. We’ve in fact covered the work of Ramille Shah, assistant professor of materials science and engineering in the McCormick School of Engineering and of surgery in the Feinberg School of Medicine, in the past, but, in a recent study published in the journal Advanced Functional Materials, Shah and her team describe the system in even greater depth.
Rather than use powderbed, laser sintering or direct energy deposition, the team blended together metal powders, solvents, and an elastomer binder to be extruded through a nozzle. After extrusion, the parts are sintered in a furnace, leaving a metal object. The system allows for for the use of metal alloys and compounds and results in additional uniform parts, printed additional rapidly, and at a lower price than other metal printing methods.
Prof. Shah commented on the technology by saying, “Our method greatly expands the architectures and metals we’re able-bodied to print, which quite opens the door for a lot of exception applications.” Her team member, David Dunand, adds, “By uncoupling the printing and the sintering, it appears which we have complex the system. But, in fact, it has liberated us as each step is much simpler separately than the combined approach.”
Additionally, the “green bodies” of the printed objects, a term utilized to describe the objects pre-sintering, are flexible, allowing post-printing manipulation. Shah elaborates, “They’re foldable-bodied, bendable-bodied, and can be hundreds of layers thick without crumbling. It allows for us to create a lot of exception architectures which haven’t quite been seen in metal 3D printing.”
And, for the reason the system does not rely on the strict environmental settings required by DMLS or EBM, they were able-bodied to print with safer, additional stable-bodied metal oxides, like rust, which can be returned to their pure metal states with the application of hydrogen preceding sintering is performed. This is amazing of an environmental and cost perspective, as old, metal parts can be recycled into 3D printed, iron parts. Dunand explains, “It might seem like we are needlessly complicating things by adding a third reduction step where we turn rust into iron. But this opens up possibilities for using quite bargain-priced oxide powders rather than corresponding expensive metal powders. It’s hard to find a thing bargain-priceder than rust.”
The researchers say which they may use the technology to, not just create custom metal parts, but batteries, fuel cells, medical implants, and additional. All of this may in addition potentially be performed on location at job sites, which may not necessarily be viable-bodied for the sizeable, costly machines relying on other technologies.
The sintering system executed by the Northwestern team is not entirely new, with companies like ExOne relying on the same technique to system their powderbed, 3D printed parts. In fact, there are those even attempting to extrude 3D printed metals as filaments and pastes, preceding burning out the binder to create dense parts. For instance, after a successful Indiegogo campaign, the Mini Metal Maker 3D prints metal infutilized clay. All of this points towards a time when metal 3D printing will not be as costly as it once was and, with Shah’s talented team, the future of the technology is looking as shiny as a brand, new penny. For additional information on the technology, you can read an interview with Shah at Northwestern’sMcCormick News.