Open Source Lemontron 3D Printer Is Ready To Build

In this era of cheap turn-key machines, the idea of actually building your own desktop 3D printer might seem odd to some. But if you’re looking for a challenge, and want to end up with a printer that legitimately sets itself apart from what they’re stocking on Amazon these days, then take a look at the Lemontron.

We’ve been keeping tabs on the development of this open source 3D printer for some time now, and just before Christmas, the files finally were released for anyone who wants to try putting one together themselves. There’s currently no formal kit available, but once you’ve printed out all the parts, there’s a very nice bill of materials you can find on the website which will tell you everything you need to complete the assembly — and critically — where you can get it.

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[James] and his Lemontron portable 3D printer

If Life Gives You Lemons, Build This Lemontron

What if your 3D printer could fit in a box of filament but still rival the build plate size of heavyweights? Enter the Lemontron, a free and open source portable printer making waves in the maker community for its compact form factor and budget-friendly price. Watch [James]’ video on his build story here. Built around the Positron drive—a unique mechanism introduced by [Kralyn] in 2022—the Lemontron is the latest evolution of this innovative design. Although Kralyn mysteriously disappeared, their work inspired other projects like the Positron JourneyMaker and this Lemontron.

The Lemontron started as a unibody chassis mod for the JourneyMaker but grew into a complete redesign, cutting costs in half without sacrificing performance. By eliminating expensive CNC parts, it’s entirely made from off-the-shelf components, bringing the build cost to just $413. Compare that to $800 for the JourneyMaker and $699 for the Positron v3.2 kit.

Overhead photo of [James]' hands assembling the Lemontron Portable 3D printerRecent video updates show the Lemontron in action, printing impressively large and complex models. It tackled a marble run with 80-degree unsupported overhangs and a ‘comically large’ Benchy, proving its capability. Its compact design, paired with robust performance, is an exciting alternative for tinkerers seeking quality on a budget.

The Lemontron is in its final development stages, with frequent updates dropping on its YouTube channel. If you’re in the market for a more “traditional” mini-printer, check out this cool suitcase model from 2014.

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Portable 3D Printer Gets Even Smaller, Faster, Better

How do you improve on a fast, capable 3D printer that sports an innovative design and is portable enough to fit in a printer spool box? Judging by what went into the Positron V3 portable printer, (video, embedded below) it takes a lot of hard work and an unwillingness to settle for compromise designs. Plus a few lucky breaks and some design wizardry.

When we first reported on [Kralyn]’s innovative “Positron” printer, its chief selling points were its portability and unique layout. With a fold-down Z-axis and a CoreXY-style drive in the base, plus an interesting 90° hot end and transparent heated build plate, the Positron managed to hit most of its design goals. But there’s always room for improvement, and Positron V3, shown in the video below, has made some pretty substantial leaps over that original concept.

The V3 design keeps the basic layout of the original, but greatly improves the usability and portability, while increasing performance and build volume. The heated borosilicate build plate is now held to the Z-axis drive with a much sturdier strut, and gets its juice through a high-temperature MagSafe connector. The X- and Y-axes are now driven by pancake steppers, which along with adding idler pulleys that are coaxial to the drive pulleys, make the CoreXY drive, and hence the printer’s base, much more compact. The printer is still much, much faster than most traditional gantry design, and print quality is on par with anything available commercially. And yes, it still fits into a standard 1-kg filament spool box when folded up.

We love this design, and the story of how the V3 came about and the intermediate V2 that didn’t make the cut is a fascinating case study in design. And as a bonus, [Kralyn] will open-source the V3 design, so you can build your own as soon as he releases the files.

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Strangest Upside-Down 3D Printer Fits In A Filament Box

It’s rare these days for a new FDM printer to come along that sparks our interest, but the [Kralyn]’s Positron managed to do it. (Video, embedded below.) It prints upside down and packs down into a filament box while still boasting a print volume of 175 mm x 176 mm x 125 mm.

Unlike most 3D printers, the hotend and XY-gantry is mounted below the build plate, directly onto the base. You might assume that a printer needs to extrude plastic with gravity to work properly, but the real action is in the smooshing of the plastic layers. It appears that it might even improve bridging since the hotend is supporting the plastic as it gets extruded. A clear glass build plate is used, with the same heating strips found on the rear windows of most cars. This also allows the user still see the part, and provides the added advantage of being able to quickly spot bed leveling and adhesion problems.

Another interesting side effect of this arrangement is rigidity. There is no need to suspend the XY gantry with the heavy hotend in the air, so it can be mounted directly on the thick aluminum base plate. It uses an H-bot style gantry, with Synchromesh timing cables instead of belts, which eliminates the concern of belt twist. To get the best possible print volume within the size of a filament box, the gantry axes are arranged diagonally across the base plate. The Z-axis can disconnect and lay flat on top of the printer and uses the linear rails to keep it perfectly straight and perpendicular when mounted. Continue reading “Strangest Upside-Down 3D Printer Fits In A Filament Box”