[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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With Core ONE, Prusa’s Open Source Hardware Dream Quietly Dies

Yesterday, Prusa Research officially unveiled their next printer, the Core ONE. Going over the features and capabilities of this new machine, it’s clear that Prusa has kept a close eye on the rapidly changing desktop 3D printer market and designed a machine to better position themselves within a field of increasingly capable machines from other manufacturers.

While some saw the incremental upgrades of the i3 MK4 as being too conservative, the Core ONE ticks all the boxes of what today’s consumer is looking for — namely high-speed CoreXY movement with a fully enclosed chamber — while still offering the build quality, upgradability, and support that the company has built its reputation on. Put simply it’s one of the most exciting products they’ve introduced in a long time, and exactly the kind of machine that many Prusa fans have been waiting for.

Unfortunately, there’s one feature that’s ominously absent from the Core ONE announcement post. It’s easy to overlook, and indeed, most consumers probably won’t even know it’s missing. But for those of us who are concerned with such matters, it’s an unspoken confirmation that an era has finally come to an end.

With the Core ONE, Prusa Research is no longer in the business of making open source 3D printer hardware, but that doesn’t mean that the printer isn’t hackable. It’s complicated, so read on.

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Tearing Down A SLA Printer With The Engineers Who Built It

Product teardowns are great, but getting an unfiltered one from the people who actually designed and built the product is a rare treat. In the lengthy video after the break, former Formlabs engineer [Shane Wighton] tears down the Form 4 SLA printer while [Alec Rudd], the engineering lead for the project, answers all his prying questions.

[Shane] was part of the team that brought all Form 4’s predecessors to life, so he’s intimately familiar with the challenges of developing such a complex product. This means he can spot the small design details that most people would miss, and dive into the story behind each one. These include the hinges and poka-yoke (error-proofing) designed into the lid, the leveling features in the build-plate mount, the complex prototyping challenges behind the LCD panel and backlight, and the mounting features incorporated into every component.

A considerable portion of the engineering effort went into mitigating all the ways things could go wrong in production, shipping, and operation. The fact that most of the parts on the Form 4 are user-replaceable makes this even harder. It’s apparent that both engineers speak from a deep well of hard-earned experience, and it’s well worth the watch if you dream of bringing a physical product to market.

You probably know [Shane] from his YouTube channel Stuff Made Here. We’ve covered many of his ludicrously challenging projects, like the auto-aiming pool cue and golf club, a robotic hairdresser, and an “unpickable” lock.

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Art of 3D printer in the middle of printing a Hackaday Jolly Wrencher logo

Hackers, Patents, And 3D Printing

Last week, we ran a post about a slightly controversial video that claimed that a particular 3D-printing slicing strategy was tied up by a patent troll. We’re absolutely not lawyers here at Hackaday, but we’ve been in the amateur 3D printing revolution since the very beginning, and surprisingly patents have played a role all along.

Modern fused-deposition modelling (FDM) 3D printing began with Stratasys’ patent US5121329A, “Apparatus and method for creating three-dimensional objects”, and the machines they manufactured and sold based on the technology. Go read the patent, it’s an absolute beauty and has 44 different claims that cover just about everything in FDM printing. This was the watershed invention, and today, everything claimed in the patent is free.

Stratasys’ patent on the fundamental FDM method kept anyone else from commercializing it until the patent expired in 2009. Not coincidentally, the first available home-gamer 3D printer, the Makerbot Cupcake, also went on sale in 2009.

The Stratasys machines were also one of the big inspirations for Adrian Bowyer to start the RepRap project, the open-source movement that basically lead to us all having cheap and cheerful 3D printers today, and he didn’t let the patent stop him from innovating before it lapsed. Indeed, the documentation for the RepRap Darwin dates back to 2007. Zach [Hoeken] Smith delivered our hackerspace the acrylic parts to make one just around that time, and we had it running a year or two before the Cupcake came out of the company that he, Bre, and Adam shortly thereafter founded.

The story of hackers and 3D printers is longer than the commercial version of the same story would imply, and a lot of important innovations have come out of our community since then too. For instance, have a look at Stratasys’ patent on heated bed technology. At first read, it seems to cover removable heated beds, but have a look at the cutout at the end of claim 1: “wherein the polymer coating is not a polymer tape”. This cutout is presumably in response to the at-the-time common practice of buying Kapton, PEI, or PET tape and applying that to removable heated bed surfaces. I know I was doing that in 2012, because I read about it on IRC or something, long before the Stratasys patent was filed in 2014. They could only get a patent for sprayed-on coatings.

As [Helge] points out, it’s also easily verifiable that the current patent on “brick layers” that we’re worrying about, filed in 2020, comes later than this feature request to Prusa Slicer that covers essentially the same thing in 2019. We assume that the patent examiner simply missed that obvious prior art – they are human after all. But I certainly wouldn’t hesitate to implement this feature given the documented timing.

I would even be so bold as to say that most of the post-2010 innovation in 3D printing has been made by hobbyists. While the RepRap movement was certainly inspired by Stratasys’ invention in the beginning, our community is where the innovation is happening now, and maybe even more starkly on the software side of things than the hardware. Either way, as long as you’re just doing it for fun, let the suits worry about the patents. Hackers gotta hack.

You Wouldn’t Download A Chair…But You Could

[Morley Kert] had a problem. He’s a big fan of the lovely Fortune Chair from Heller Furniture. Only, he didn’t want to pay $1,175 for a real one. The solution? He printed his own instead!

The basic concept is simple. Capture or recreate the geometry of the fancy expensive designer chair, and then print it out on a 3D printer. That would be easy, except for scale. Chairs have to be both big enough to seat humans, and strong enough to carry their weight. For the average 3D printer owner, meeting the big requirement is difficult, since most printers are quite small compared to chairs.

[Morley] gets around this in the typical fashion—he prints the chair in multiple segments. Indeed, we’ve seen [Morley] tackle a similar project before, too. Only, last time, he had the benefit of a print farm and some easily-accessible geometry for the target object. This time, he’s working very much more from scratch, and chose to print everything at home. That made things quite a bit harder.

Scaling up is never as easy at it seems at first!

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Excerpt from 1995 Stratasys patent, showing the drawings of FDM layers, including brick layers.

Brick Layers: The Promise Of Stronger 3D Prints And Why We Cannot Have Nice Things

It is a fact of life that 3D printed parts from an FDM (fused deposition modeling) printer have weaknesses where the layers join. Some of this is due to voids and imperfect layer bonding, but you can — as [Geek Detour] shows us — work around some of this. In particular, it is possible to borrow techniques from brick laying to create a pattern of alternating blocks. You can check out the video below.

The idea of ‘brick layers’ with FDM prints was brought to the forefront earlier this year by [Stefan] of CNC Kitchen. Seven months after that video you still can’t find the option for these layers in any popular slicers. Why? Because of a 2020 patent filed for this technique by a 3D printing company which offers this feature in its own slicer. But is this patent even valid?

It’s no surprise that prior art already exists in the form of a 1995 Stratasys patent. The above image shows an excerpt from the 1995 Stratasys patent, covering the drawings of FDM layers, including brick layers. This covered all such ways of printing, but the patent expired in 2016. In 2019, a PrusaSlicer ticket was opened, requesting this feature. So what happened? A second patent filed in 2020 assigned to Addman Intermediate Holdings: US11331848B2.

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All Aboard The Good Ship Benchy

We’ll go out on a limb here and say that a large portion of Hackaday readers are also boat-builders. That’s a bold statement, but as the term applies to anyone who has built a boat, we’d argue that it encompasses anyone who’s run off a Benchy, the popular 3D printer test model. Among all you newfound mariners, certainly a significant number must have looked at their Benchy and wondered what a full-sized one would be like. Those daydreams of being captain of your ship may not have been realized, but [Dr. D-Flo] has made them a reality for himself with what he claims is the world’s largest Benchy. It floats, and carries him down the waterways of Tennessee in style!

The video below is long but has all the details. The three sections of the boat were printed in PETG on a printer with a one cubic meter build volume, and a few liberties had to be taken with the design to ensure it can be used as a real boat. The infill gaps are filled with expanding foam to provide extra buoyancy, and an aluminium plate is attached to the bottom for strength. The keel meanwhile is a 3D printed sectional mold filled with concrete. The cabin is printed in PETG again, and with the addition of controls and a solar powered trolling motor, the vessel is ready to go. Let’s face it, we all want a try!

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