3D Printering: Liquid-Filled Filament Was Not On Our Bingo Card

November 2, 2025 by Donald Papp 24 Comments

[Prusa] have a number of announcements, and one of the more unusual ones is that liquid printing is coming to the Prusa XL. Specifically, printing in real, heat-resistant silicone (not a silicone-like plastic) is made possible thanks to special filament and a special toolhead. It’s the result of a partnership with Filament2, and the same process could even be used to print with other liquids, including chocolate.

Look closely and you will see the detail in the nozzle, which mixes the two-part formula.

The process is as unusual as it is clever. The silicone is a two-part formula, but there is no reservoir or pump involved. Instead, there are two filaments, A and B. When mixed, they cure into solid silicone.

What is unusual is that these filaments have a liquid core. Upon entering the extruder, the outer sheath is cut away, and the inner liquid feeds into a mini mixing nozzle. The nozzle deposits the mixed silicone onto the print, where it cures. It isn’t clear from the demo where the stripped outer casing goes, but we assume it must get discarded or is possibly stowed temporarily until it can be removed.

Liquid-core filament is something we certainly didn’t have on our bingo card, but we can see how it makes sense. A filament format means the material can be handled, fed, and deposited precisely, benefiting from all of the usual things a filament-based printer is good at doing.

What’s also interesting is that the liquid toolhead can co-exist with other toolheads on the XL; in fact, they make a point of being able to extrude silicone as well as the usual thermoplastics into the same print. That’s certainly a trick no one else has been able to pull off.

There are a few other announcements as well, including a larger version of their Core One printer and an open-source smart spool standard called OpenPrintTag, a reusable and reprogrammable NFC insert for filament spools that gives you all of the convenience of automating color and material reading without the subtle (or overt) vendor lock-in that comes with it.

Watch a demo of the new silicone extruder in the video, embedded just under the page break. The new toolhead will be 1,009 USD when it launches in early 2026.

Continue reading “3D Printering: Liquid-Filled Filament Was Not On Our Bingo Card” →

Liquid Silicone 3D Printing Is No Joke

May 7, 2025 by Tyler August 45 Comments

They might call it Levity, but there’s nothing funny about Rapid Liquid Print’s new silicone 3D printer. It has to be seen to be believed, and luckily [3D Printing Nerd] gives us lots of beauty shots in this short video, embedded below.

Smooth, and *fast*. This bladder took 51 minutes according to the RLP website.

Printing a liquid, even a somewhat-viscous one like platinum-cure silicone, presents certain obvious challenges. The Levity solves them with buoyancy: the prints are deposited not onto a bed, but into a gel, meaning they are fully supported as the silicone cures. The fact that the liquid doesn’t cure instantly has a side benefit: the layers bleed into one another, which means this technique should (in theory) be stronger in all directions than FDM printing. We have no data to back that up, but what you can see for yourself that the layer-blending creates a very smooth appearance in the finished prints.

If you watch the video, it really looks like magic, the way prints appear in the gel. The gel is apparently a commercially-available hydrogel, which is good since the build volume looks to need ̶a̶b̶o̶u̶t̶ ̶5̶0̶0̶ ̶L̶ at least 125 L of the stuff. The two-part silicone is also industry-standard and off-the-shelf, though no doubt the exact ratios and are tweaked for purpose. There’s no magic, just a really neat technology.

If you want one, you can sign up for the waiting list at Rapid Liquid Print’s website, but be prepared to wait; units ship next year, and there’s already a list.

Alternatively, since there is no magic here, we’d love to see someone take it on themselves, the way once equally exotic SLS printers have entered the DIY world. There was a time when resin printers were new and exotic and hobbyists had to roll their own, too. None of this is to say we don’t respect the dickens out of the Rapid Liquid Print team and their achievement–it’s just that imitation is the sincerest form of flattery. Continue reading “Liquid Silicone 3D Printing Is No Joke” →