Self-assembling Polymers Support Silicone 3D Prints

We all know what the ultimate goal of 3D printing is: to be able to print parts for everything, including our own bodies. To achieve that potential, we need better ways to print soft materials, and that means we need better ways to support prints while they’re in progress.

That’s the focus of an academic paper looking at printing silicone within oil-based microgels. Lead author [Christopher S. O’Bryan] and team from the Soft Matter Research Lab at the University of Florida Gainesville have developed a method using self-assembling polymers soaked in mineral oil as a matrix into which silicone elastomers can be printed. The technique takes advantage of granular microgels that are “jammed” into a solid despite being up to 95% solvent. Under stress, such as that exerted by the nozzle of a 3D printer, the solid unjams into a flowing liquid, allowing the printer to extrude silicone. The microgel instantly jams back into a solid again, supporting the silicone as it cures.

[O’Bryan] et al have used the technique to print a model trachea, a small manifold, and a pump with ball valves. There are Quicktime videos of the finished manifold and pump in action. While we’ve covered flexible printing options before, this technique is a step beyond and something we’re keen to see make it into the hobby printing market.

[LonC], thanks for the tip.

3D Printing Without Support

3D printing is getting better every year, a tale told by dozens of Makerbot Cupcakes nailed to the wall in hackerspaces the world over. What was once thought impossible – insane bridging, high levels of repeatability, and extremely well-tuned machines – are now the norm. We’re still printing with supports, and until powder printers make it to garages, we’ll be stuck with that. There’s more than one way to skin a cat, though. It is possible to print complex 3D objects without supports. How? With pre-printed supports, of course.

[Markus] wanted to print the latest comet we’ve landed on, 67P/Churyumov–Gerasimenko. This is a difficult model for any 3D printer: there are two oversized lobes connected by a thin strand of comet. There isn’t a flat space, either, and cutting the model in half and gluing the two printed sides together is certainly not cool enough.

To print this plastic comet without supports, [Markus] first created a mold – a cube with the model of the comet subtracted with a boolean operation. If there’s one problem [Markus] ran into its that no host software will allow you to print an object over the previous print. That would be a nice addition to Slic3r or Repetier Host, and shouldn’t be that hard to implement.