Liquid Silicone 3D Printing Is No Joke

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”

FLOSS Weekly Episode 832: Give Yourself A Medal

This week, Jonathan Bennett chats with Alexandre Dulaunoy and Quentin Jérôme about Kunai and CIRCL! How does Kunai help solve Linux security monitoring? Why is eBPF the right place for one of these tools to run? And how is CIRCL helping Luxembourg and the world deal with the modern security landscape? Watch to find out!

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Cabinentaxi layout as it existed in 1978, with labels by the Tim Traveller YT channel.

Germany’s Cabinentaxi: The Double-Sided Monorail That Wasn’t Meant To Be

The 1970s was a perfect time for alternative modes of transport to be trialed that might replace cars in the wake of the global oil crisis. One of these was the Cabinentaxi, or C-Bahn as it was later called, which was a variation on the standard suspended and monorail concepts.

It was a people mover concept, with ‘pods’ (or cabins) that’d ride either on top of or below the suspended track. It was tested intensively over the course of six years, performed admirably, and completely failed to materialize commercially due to budget crunch times around the world.

Image of the Cabinentaxi from a promotional video, showing carriages on top and below the monorail.

Recently [Tim Traveller] went to the muddy farm field that once housed the big test track (pictured above), of which nothing remains but the gates and a sign. Despite the fact that few people have heard of Cabinentaxi prior to seeing [Tim]’s video or reading this, there is a big Wikipedia entry on it, as well as a (German language) site dedicated to the technology.

What made the C-Bahn different from trains and buses were the smaller pods, high throughput capacity and ability to call a pod on demand at any of the stations. This kind of flexibility is what is seen more or less with today’s people moving systems at airports and some cities, except the C-Bahn was classified as a personal rapid transport (PRT), with on-demand pods that could travel between any two stations without stopping or delays. This is something that isn’t seen with public transport today, even if self-driving cars purport to one day do this kind of trick.

Considering that this technology died most due to economical circumstances, we remain hopeful to see its revival one day.

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Big Chemistry: Cement And Concrete

Not too long ago, I was searching for ideas for the next installment of the “Big Chemistry” series when I found an article that discussed the world’s most-produced chemicals. It was an interesting article, right up my alley, and helpfully contained a top-ten list that I could use as a crib sheet for future articles, at least for the ones I hadn’t covered already, like the Haber-Bosch process for ammonia.

Number one on the list surprised me, though: sulfuric acid. The article stated that it was far and away the most produced chemical in the world, with 36 million tons produced every year in the United States alone, out of something like 265 million tons a year globally. It’s used in a vast number of industrial processes, and pretty much everywhere you need something cleaned or dissolved or oxidized, you’ll find sulfuric acid.

Staggering numbers, to be sure, but is it really the most produced chemical on Earth? I’d argue not by a long shot, when there’s a chemical that we make 4.4 billion tons of every year: Portland cement. It might not seem like a chemical in the traditional sense of the word, but once you get a look at what it takes to make the stuff, how finely tuned it can be for specific uses, and how when mixed with sand, gravel, and water it becomes the stuff that holds our world together, you might agree that cement and concrete fit the bill of “Big Chemistry.”

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Adorable Robot Steals The Show

An ongoing refrain with modern movies is “Why is all of this CG?”– sometimes, it seems like practical effects are simultaneously a dying art, while at the same time modern technology lets them rise to new hights. [Davis Dewitt] proves that second statement with his RC movie star “robot” for an upcoming feature film.

The video takes us through the design process, including what it’s like to work with studio concept artists. As for the robot, it’s controlled by an Arduino Nano, lots of servos, and a COTS airplane R/C controller, all powered by li-po batteries. This is inside an artfully weathered and painted 3D printed body. Apparently weathering is important to make the character look like a well-loved ‘good guy’. (Shiny is evil, who knew?) Hats off to [Davis] for replicating that weathering for an identical ‘stunt double’.

Check out the video below for all the deets, or you can watch to see if “The Lightning Code” is coming to a theater near you. If you’re into films, this isn’t the first hack [Davis] has made for the silver screen. If you prefer “real” hacks to props, his Soviet-Era Nixie clock would look great on any desk. Thanks to [Davis] for letting us know about this project via the tips line.

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DIY Penicillin

We don’t often consider using do-it-yourself projects as a hedge against the apocalypse. But [The Thought Emporium] thinks we should know how to make penicillin just in case. We aren’t so sure, but we do think it is a cool science experiment, and you can learn how to replicate it in the video below.

If you want to skip the history lesson, you need to fast-forward to about the six-minute mark. According to the video, we are surrounded by mold that can create anti-bacterial compounds. However, in this case, he starts with a special strain of mold made to produce lots of antibiotics.

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Five Oddest Op Amp Applications

You think of op amps as amplifiers because, no kidding, it is right in the name. But just like some people say, “you could do that with a 555,” [Doctor Volt] might say, “you can do that with an op amp.” In a recent video, you can see below, he looks at simulations and breadboards for five applications that aren’t traditional amplifiers.

Of course, you can split hairs. A comparator is sort of an amplifier with some very specific parameters, but it isn’t an amplifier in the classic sense.

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