The Tantillus, Reborn

In the beginning, around 2011 or thereabouts, there was an infinite variety of designs available for anyone to build their own 3D printer. There were Mendels, some weirdos were actually trying to build Darwins, and deltas were starting to become a thing. In the years since then, everyone just started buying cheap Prusa clones and wondering why their house burnt down.

One of the most innovative printers of this era was the Tantillus. It was a small printer, with the entire frame fitting in a 250mm square, but still able to print a 100mm cube. You could print the entire printer, and it was adorable. Face it: most of your prints aren’t bigger than 100mm unless you’re purposely printing something huge, and having a low moving mass is good.

The Tantillus has fallen by the wayside, but now it’s back. The Tantillus R — the ‘R’ means ‘reborn’ — is the latest project to take the design goals of the original Tantillus and bring it into the era of the modern RepRap ecosystem. (German, Google Translatrix, but the English translation of all the documentation is in the works),

Of note in this new design, the Tantillus R is still using shafts driven with high-test fishing line, driven by steppers and belts. The R version is getting away from the J-head, but in the interests in keeping the moving mass down, the hotend is a Merlin. This might seem an especially odd choice in the age of all-metal hotends, but again the goal is to keep moving mass down. As you would expect from a modern 3D printer, there’s support for a heated bed, you can plug a Raspberry Pi into it for Octoprint, and in true RepRap fashion, most of the parts are printable.

While the era of self-build 3D printers is probably over — you can’t compete with the cheap Chinese firestarters on price — the Tantillus R is a great project that retains the spirit of the RepRap projects while adding a few modern niceties and can still produce some impressive prints.

MRRF: Launching an Adorable Printer For Fun

Patrick and Matt hold a running Kitten Printer. The frame is stiff enough that the printer can be held or turned upside down and it can keep printing.
Patrick and Matt hold a running Kitten Printer. The frame is stiff enough that the printer can be held or turned upside down and it can keep printing without visible defects in the print.

[Patrick] and [Matt] have been coming to the Midwest RepRap Festival from Minneapolis for the past few years and bringing their trusty Tantillus printers with them. However, sometime between this year and the last [Patrick] decided that it would be really fun to make his own 3D printer, and liking the size and accuracy of the Tantillus, started there.

The adorably sized printer is adorably named too: Kitten 3D printer. The printer is certainly an enthusiast’s choice. It’s expensive at 1200 and small, but very well made. Its one big advantage?  It prints really accurate parts.

The Tantillus also printed well, but the extruder left a lot to be desired, and the low stretch fishing line movement was very difficult to get tensioned just right. The secret behind the Tantillus and Kitten’s great print quality, aside from good design, is the small xy movement and low weight of the extruder set-ups. By having a movement over a very small range, cumulative errors in construction never get to add up. Also vibrations are less likely to show and smaller moments on the joints mean less flex at the extremes of the movements.

Really stunning print quality almost entirely free of ringing and z-wobble.
Really stunning print quality almost entirely free of ringing and z-wobble. 100mm x 100mm tray. These are very small parts.

[Patrick] is a mechanical engineer for his day job, and since this was a just for fun printer, he cut no corners. The frame is made with Misumi extrusions and linear movements. The build plate sits on a machined aluminum plate. It’s not flexing or going anywhere.

Part of what really stood out to me about the printer are a lot of neat little features which show careful thought. For example, the extruder movement sits neatly under one of the motors. All the parts except for one can be printed inside its build envelope without support. It uses around 200g of plastic. Every axis is constrained just enough, rather than the common tendency to over constrain that plagues 3D printer design. The spec sheet reads like my printer part wishlist: Bondtech extruder, Rambo board, E3d nozzle, heated bed, flat borosilicate build plate, name brand linear movements, and a well designed Z.

cleverdetails
The entire extruder assembly tucks under one of the XY motors at the corner of its movement. Compare its size to the size of a NEMA14 stepper motor.

Another interesting aspect of the design is the extremely light extruder assembly. The lighter an extruder can get, the less ringing will show in your parts at speed. This is one of the most compact designs I’ve witnessed. It consists of two fans, an E3d v6 lite nozzle, and two small linear bearings. The cold end is handled by a bowden set-up and a Bondtech extruder at the back of the printer. The only way to get it lighter would be a different nozzle, such as the upcoming insanely light 13g Pico from B3 unveiled at the festival. I was also interested to see that the bearings on the supporting rails were printed bushings to keep the weight even lower. [nop head] has tested these extensively, they should be fine as long as the rods have a good finish.

I’ve mentioned the size before, but it’s hard to grasp just how adorable this printer is without seeing it. The build envelope is 100mm x 100mm x 100mm, the printer itself is 200mm x 200mm x 240mm. That’s only 50mm wider than the build footprint. It’s a really fun design just to look at and see how they fit it all in there. There are lots of neat little tricks with belt routing and part design to get it all right.

For the enthusiast this would make a good small parts printer and travel printer. However, for me, it was neat to see people still setting out to try designing their own printer. In some ways the 3d printer movement has become crowded with Chinese knock-offs, and I was excited to see something new at the festival. It wasn’t the only new printer design there, but it stood out to me the most. I like the uncompromising nature of it, many people try to design for the lowest BOM and not the nicer print. There are still lots of low-hanging fruit in the 3d printer world and many of them are just getting the mechanics right.

[Patrick] and [Matt] came to the festival with their printer to see if people would like it. They didn’t have grand dreams of selling tons of printers and making millions. They were quite aware that their price point and the small size made it not for everyone. However, their table always had a small crowd. They just really like 3D printers, and that honesty resonated. They didn’t even have a website up at the start of the convention, but by the end they had gotten so many requests they had to oblige. They expect to have 3 kit options available by the end of April. If you’re interested there’s a mailing list sign up on their website. Let’s hope we see them at MRRF again next year with another cool design to look over.