3D Printing Progress

There’s going to be a lot of that, now that critical mass of commercial systems are available. new materials are being used in additive manufacturing and new devices have considerably expanded the capabilities of systems in terms of speed, build volume and finish. It’s an interesting moment in engineering history, and nobody knows where it will lead.

Printing with [anything besides plastics] is fraught with difficulty, so interesting methods have been tried for substances like metals, clay, frosting(!) with varying success. Two methods have lately shown promise in metal and glass(amazingly enough).

First, metals. The most common method of depositing metals has been to embed the metal in something a bit more fluid, like in an ink suspension. This has the usual effect of having poor mechanical adhesion, because after the fluid dries the metal may adhere to itself poorly (likely) and there may be fluid contamination trapped in the metal layers (very likely).  Researchers got around this with an entirely new method, using a sacrificial electrode to generate ions of the metal and spraying those ions electrostatically. You can get insanely small resolution using this technique:

…and you can print with more than one metal by building both into the tip and just switching voltage from one electrode to the other:

Elegant as hell, isn’t it?

Then, glass: a team in France using chalcogenide glass (which softens at a relatively low temperature compared to other glass) produced chalcogenide glass filaments with dimensions similar to the commercial plastic filaments normally used with the 3-D printer. The research team then increased the maximum extruding temperature of a commercial 3-D printer from around 260 °C to 330 °C.  The result is pretty interesting:

An interesting proof-of-concept piece, this points to novel uses for chalcogenide glass commonly used to make optical components that operate at mid-infrared wavelengths. It’s not likely to be used elsewhere, as it’s a “soft” glass, but the feat is going to be useful in optics fabrication. Also, there are some low-temperature metal alloys that could probably benefit from this technique.

 

Homework: Alain Reiser et al. Multi-metal electrohydrodynamic redox 3D printing at the submicron scale, Nature Communications (2019). DOI: 10.1038/s41467-019-09827-1

E. Baudet et al, 3D-printing of arsenic sulfide chalcogenide glasses, Optical Materials Express (2019). DOI: 10.1364/OME.9.002307