Embedded 3D Printing With Liquids On A Bricked Prusa FDM Printer

October 9, 2026 by Maya Posch 6 Comments

Recently [Riley] got his paws on an old Prusa i3 FDM printer that had clearly seen better days, with a hot-end that had suffered an explosive blow-out. For the project he had in mind this was of course perfect, as his intention was to replace the hot-end with a syringe system for embedded 3D printing (E3DP), which uses a supportive medium to allow for the printing of materials and structures that would be impossible with just air.

Generally in additive manufacturing (AM) methods like fused deposition modelling (FDM) the material is extruded onto a build plate or a previous layer where it solidifies. This works great for materials like thermoplastics, but for other materials having only the surrounding air as support is just a recipe for a big mess. With E3DP the liquid is instead extruded into a supportive material at a selectable depth and volume, opening up a whole range of possibilities.

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A Headset Fit For A Hackaday Writer

October 6, 2026 by Jenny List 22 Comments

I started writing this from a commuter train passing at speed through the outskirts of London, and my headset had just broken. The flexible joint that attaches one earpiece to the headband has snapped, leaving the earpiece dangling on its cable. This is annoying on its own, but what is annoying me enough to write about it is that this isn’t the first time. This is only the latest in a succession of headsets I’ve taken on the road with me has broken, not because of rough treatment, but simply due to flimsy or bad design. What on earth can I do about this?

Failure Built-In

The earpiece of an EPOS headset, detached from its band. — Failure inevitable: the whole headset relied on a tiny piece of plastic in the centre.

The most recent three have been a JVC whose rotating joint allowing the earpiece to lie at a slight angle with my ear has failed, a quite expensive Logitech whose ear sponges failed closely followed by its USB cable, and now an EPOS whose ball joint has failed.

I repaired the JVC and got a bit more life out of it and I’ll have a go at repairing this EPOS, but that’s hardly the point. I’m paying not inconsequential money and I’m getting good sound quality and electronics, but I’m not getting anywhere near the mechanical quality I need. I could buy a set of tough DJ headphones such as the Sennheiser HD25, but they don’t come with a microphone, they’re not a headset.

So if I can’t buy a decent headset without spending military grade money on one from an F16 fighter, what can I do to make my own? I’m an engineer, damnit!

At its most basic, a headset is a springy band that goes over the head, with an earpiece at its end. But a human head is not a cube with vertical parallel sides, it’s a complex shape and every one is different. So those earpieces have to have some “give” in them in order to fit comfortably against the ear. In the simplest case this is achieved by giving the earpiece a soft surround that moulds itself to the ear, but most headsets incorporate some articulation. The earpiece must rotate a little around a vertical line parallel with the ear, and also with a horizontal line at right angles to the axis of the ear. The EPOS managed both axes by means of a ball joint, while the JVC had a stirrup with pins to achieve the horizontal motion, and a circular joint — the part which broke — for the vertical. In both case the weak point was a thin part of the plastic moulding which broke, on the EPOS a short stalk for the ball in the ball joint, and in the JVC a similar stalk for the circular joint. Any design I come up with must avoid this type of weak point, and spread the load of an earpiece over considerably more material than my broken headset. Continue reading “A Headset Fit For A Hackaday Writer” →

3D-Printed Filter Removes Most Microplastics From Water

October 5, 2026 by Maya Posch 20 Comments

With the rise of synthetic polymers in everywhere from clothing, packaging and beyond, we have also seen a corresponding rise in fragments of these polymers in the environment. These micro- and nanoplastics (MNPs) come in a wide variety of sizes, but have in common that they do not break down very easily, leaving filtration as an important way to keep them out of our potable water sources. A recent paper by [Ethan A. Crawford] et al. in Separation and Purification Technology details a way to use a low-cost, 3D-printed filtration mesh to filter out up to 90% of MNPs using their prototype.

This prototype uses a multi-layer filtration system printed in PLA, creating a flow-through system in which polyethylene glycol (PEG) acts as a sacrificial additive to the PLA. Whereas creating the fine pores required for filtration of MNPs is impossible using FDM printing, the spheres of PEG that form inside the printed filter can be subsequently etched away using nothing but hot (80°C) water, leaving behind a porous surface capable of trapping fine particles.

These pores are characterized in the paper, with the PLA-PEG10 sample showing the best porous structure while maintaining structural integrity of the PLA material. With 20 layers of these filters a filtration efficiency of 90% was achieved, though as the authors note aspects like improving the system and potential reusability still have to be investigated.

We have previously looked at MNPs, including how little we know about how many of them really are inside our bodies right now, and how lab gloves may be contaminating test results.

Designing A Fully 3D-Printed Mechanical Calculator

September 29, 2026 by Maya Posch 9 Comments

Even if almost tragically impractical in a world where digital calculators are cheap as chips, mechanical calculators and their big mechanical computer brethren remain an absolute marvel of engineering. Using nothing but elements like simple gears their motion is used to calculate everything from a simple multiplication to the proper targeting instructions for an Iowa-class battleship’s guns.

This fascination, along with the mind-bendingly high prices for commercial digital calculators led [3D all Workshop] to spend 2 months on designing his own mechanical calculator. Fully FDM 3D-printed, of course.

In the video the design process and troubleshooting step are covered along with the workings of the mechanisms for both addition and multiplication. While this may seem simple, basically converting numbers of rotations into a final indicator position, aspects like carrying a digit and adding a multiplication feature to the mechanism require some proper engineering.

Of course, using FDM printing for tolerance-sensitive things like gears meant that a lot of time was spent redesigning aspects of the mechanism, going through about a hundred design iterations until it worked, with the help from a bit of lubrication.

Naturally this isn’t the first 3D-printed mechanical calculator, not to mention ones made from wood, but always it’s pretty cool to see one made from first fundamentals.

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Forget Trees, Add Fins To Your 3D Prints Instead

September 23, 2026 by Maya Posch 23 Comments

Perhaps one of the most contentious issues in 3D printing is that of supports, both because they’re an uncomfortable reminder of how gravity affects our prints and because the very idea of there being ‘one right way’ is bound to get you into some spirited discussions. That said, [Matthew Trahan] figured that neither regular grid supports nor organic tree supports are the answer here, and that the better answer is found in fins.

The problem with existing support approaches especially with FDM prints is that they can be fairly wasteful in terms of material, and they can leave serious marks on the printed object’s surface that require post-processing. These fins on the other hand are designed to require as little material as possible and snap off as cleanly as possible. The tool, developed with the assistance of Claude, can either run locally or be accessed via printfins.com.

Currently the idea is that these fins are baked directly into the STL model so that it’s a one-time thing, but it may eventually become available as a slicer plugin. The basic concept was pitched by [Slant3D], who gets credited in the video below, although in their approach they used CAD software to add the fin supports manually.

The fins are there to provide the support base, while small tines can be added to reinforce the connection to the model. These do make it less easy to snap off with minimal scarring, of course. Conceivably these fins could be made even more light-weight by adding gaps, but that probably would add to the print time.

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Full-Color Looks Great On 3D Printed Sliding Puzzles

September 16, 2026 by Donald Papp 4 Comments

[Angus] of [Maker’s Muse] shows off both a parametric, print-in-place sliding puzzle design he created, and the results of UV printing full-color designs on the same. The results look beautiful, and there was a whole lot of trial and error involved in the process.

The design includes a pop-out tile, which can be re-inserted to a finished puzzle.

Creating a good print-in-place sliding puzzle depends a lot on tolerances. Today’s 3D printers are much more capable in this regard than they were ten or so years ago, but getting the right feel to the pieces was still a long learning process. It’s not at all easy to get all the different characteristics in the right balance. On one hand, if the pieces are too tight they won’t slide easily. But if they are too loose, the puzzle can bind because the pieces have too much play. It may also flex enough to pop apart. And of course, the shape of the pieces and their mating surfaces are constrained to angles and shapes that 3D print reliably. [Angus] persevered and succeeded, and shows off everything from cute 3 x 3 units to a massive scaled-up 11 x 11 puzzle, printed on his Prusa XL.

Getting the color onto the print is the work of a desktop UV ink printer, the same model our own Tom Nardi had a hands-on look at last year. [Angus] shows how printing a single color image onto the puzzle is pretty easy and looks great, but what’s even better is a textured relief image with some real tactile depth to it. Expect a lot more work to do for that, because thick layers of ink gum the puzzle up with overspray unless one avoids printing over the gaps in the tiles.

Watch both the puzzles and the color printing in action in his video, embedded just below.

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Changing Nozzle Internal Geometry To Increase FDM Flowrate

September 10, 2026 by Maya Posch 20 Comments

As FDM printers keep getting faster, we are forced to deal with a range of bottlenecks, all of which conspire to hold us back from another Benchie world record. A major physical limitation is that of flowrate, as the hotend has to be able to melt the filament that enters the nozzle before it departs said nozzle. One attempt to make a high-flow nozzle involves splitting the material path into three winding sections, which theoretically should help said flowrate. Recently [Thomas Sanladerer] took a poke at this and other types of nozzle with SLS-printed nozzles.

These printed parts still needed some finishing on the lathe, including drilling the 0.4 mm nozzle hole. The finished nozzles feature a variety of internal geometries, including the aforementioned triple-path, as well as many with various intrusions that seek to maximize the contact area.

Using a Prusa Core One these nozzles were subsequently tested to see what print quality they produced at high flow rates. A special test rig to test the nozzle pressure was also used to further characterize them, as this indicates at which flowrate the nozzle begins to struggle. Among these the Fuge design did the best, though with the big asterisk that these nozzles were printed in MS1, which is in effect tool steel and thus not great for being nozzles.

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