3d Printer hacks

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Introducing PooLA Filament: Grass Fiber-Reinforced PLA

July 14, 2025 by 20 Comments

We’re probably all familiar with adding wood dust, hemp and carbon fibers to PLA filament, but there are so many other fillers one could add. During the completely unrelated recent heatwave in Germany, [Stefan] from CNCKitchen decided to give a new type of biodegradable filler type a shot by scooping some freshly dried cow patties off the very picturesque grazing fields near his place. In the resulting video a number of questions are answered about this ‘PooLA’ that nobody was asking, such as whether it makes for a good filler, and whether it smells bad while printing.

Perhaps unsurprisingly to those who have spent any amount of time around large herbivores like cows, cow dung doesn’t smell bad since it’s mostly composed of the grass fibers that are left over after the cow’s multiple stomachs and repeated chewing have done their thing. As [Stefan] and his colleagues thus found out was that printing with PooLA smells like printing with grass.

As for the practical benefits of PooLA, it adds a nice coloring, but like other ‘reinforced’ PLA filaments seems to trade flexibility for stiffness, so that at ratios of cow dung powder between 5 to 20% added to the PLA powder the test parts would break faster. Creating the filament was also a bit of a chore, for reasons that [Stefan] still has to figure out.

That said, aside from the technically unneeded bacterial corpses and other detritus in cow patties, using grass fibers in FDM filament isn’t a crazy idea, and might fit right in there with other fibers.

Continue reading “Introducing PooLA Filament: Grass Fiber-Reinforced PLA” →

A 3D printer is in the process of printing a test piece. The printer has two horizontal linear rails at right angles to each other, with cylindrical metal rods mounted horizontally on the rails, so that the rods cross over the print bed. The print head slides along these rods.

An Open-Concept 3D Printer Using Cantilever Arms

July 12, 2025 by 13 Comments

If you’re looking for a more open, unenclosed 3D printer design than a cubic frame can accommodate, but don’t want to use a bed-slinger, you don’t have many options. [Boothy Builds] recently found himself in this situation, so he designed the Hi5, a printer that holds its hotend between two cantilevered arms.

The hotend uses bearings to slide along the metal arms, which themselves run along linear rails. The most difficult part of the design was creating the coupling between the guides that slides along the arms. It had to be rigid enough to position the hotend accurately and repeatably, but also flexible enough avoid binding. The current design uses springs to tension the bearings, though [Boothy Builds] eventually intends to find a more elegant solution. Three independent rails support the print bed, which lets the printer make small alterations to the bed’s tilt, automatically tramming it. Earlier iterations used CNC-milled bed supports, but [Boothy Builds] found that 3D printed plastic supports did a better job of damping out vibrations.

[Boothy Builds] notes that the current design puts the X and Y belts under considerable load, which sometimes causes them to slip, leading to occasional layer shifts and noise in the print. He acknowledges that the design still has room for improvement, but the design seems quite promising to us.

This printer’s use of cantilevered arms to support the print head puts it in good company with another interesting printer we’ve seen. Of course, that design element does also lend itself to the very cheapest of printers.

Continue reading “An Open-Concept 3D Printer Using Cantilever Arms” →

Trickle Down: When Doing Something Silly Actually Makes Sense

July 12, 2025 by 10 Comments

One of the tropes of the space race back in the 1960s, which helped justify the spending for the part of the public who thought it wasn’t worth it, was that the technology developed for use in space would help us out here back on earth. The same goes for the astronomical expenses in Formula 1, or even on more pedestrian tech like racing bikes or cinematography cameras. The idea is that the boundaries pushed out in the most extreme situations could nonetheless teach us something applicable to everyday life.

This week, we saw another update from the Minuteman project, which is by itself entirely ridiculous – a 3D printer that aims to print a 3D Benchy in a minute or less. Of course, the Minuteman isn’t alone in this absurd goal: there’s an entire 3D printer enthusiast community that is pushing the speed boundaries of this particular benchmark print, and times below five minutes are competitive these days, although with admittedly varying quality. (For reference, on my printer, a decent-looking Benchy takes about half an hour, but I’m after high quality rather than high speed.)

One could totally be forgiven for scoffing at the Speed Benchy goal in general, the Minuteman, or even The 100, another machine that trades off print volume for extreme speed. But there is definitely trickle-down for the normal printers among us. After all, pressure advance used to be an exotic feature that only people who were using high-end homemade rigs used to care about, and now it’s gone mainstream. Who knows if the Minuteman’s variable temperature or rate smoothing, or the rigid and damped frames of The 100, or its successor The 250, will make normal printers better.

So here’s to the oddball machines, that push boundaries in possibly ridiculous directions, but then share their learnings with those of us who only need to print kinda-fast, but who like to print other things than little plastic boats that don’t even really float. At least in the open-source hardware community, trickle-down is very real.

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Double Your Printing Fun With Dual-Light 3D Printing

July 10, 2025 by 9 Comments

Using light to 3D print liquid resins is hardly a new idea. But researchers at the University of Texas at Austin want to double down on the idea. Specifically, they use a resin with different physical properties when cured using different wavelengths of light.

Natural constructions like bone and cartilage inspired the researchers. With violet light, the resin cures into a rubbery material. However, ultraviolet light produces a rigid cured material. Many of their test prints are bio-analogs, unsurprisingly.

Continue reading “Double Your Printing Fun With Dual-Light 3D Printing” →

The crank/keying assembly

Hacking A Guitar Into A Hurdy-Gurdy Hybrid With 3D Prints

July 10, 2025 by 10 Comments

If you’re looking for a long journey into the wonderful world of instrument hacking, [Arty Farty Guitars] is six parts into a seven part series on hacking an existing guitar into a guitar-hurdy-gurdy-hybrid, and it is “a trip” as the youths once said. The first video is embedded below.

The Hurdy-Gurdy is a wheeled instrument from medieval europe, which you may have heard of, given the existence of the laser-cut nerdy-gurdy, the electronic midi-gurdy we covered here, and the digi-gurdy which seems to be a hybrid of the two. In case you haven’t seen one before, the general format is for a hurdy-gurdy is this : a wheel rubs against the strings, causing them to vibrate via sliding friction, providing a sound not entirely unlike an upset violin. A keyboard on the neck of the instrument provides both fretting and press the strings onto the wheel to create sound. 

[Arty Farty Guitars] is a guitar guy, so he didn’t like the part with about the keyboard. He wanted to have a Hurdy Gurdy with a guitar fretboard. It turns out that that is a lot easier said than done, even when starting with an existing guitar instead of from scratch, and [Arty Farty Guitar] takes us through all of the challenges, failures and injuries incurred along the way. 

Probably the most interesting piece of the puzzle is the the cranking/keying assembly that allows one hand to control cranking the wheel AND act as keyboard for pressing strings into the wheel. It’s key to the whole build, as combining those functions on the lower hand leaves the other hand free to use the guitar fretboard half of the instrument. That controller gets its day in video five of the series. It might inspire some to start thinking about chorded computer inputs– scrolling and typing?

If you watch up to the sixth video, you learn that that the guitar’s fretting action is ultimately incompatible with pressing strings against the wheel at the precise, constant tension needed for good sound. To salvage the project he had to switch from a bowing action with a TPU-surfaced wheel to a sort of plectrum wheel, creating an instrument similar to the thousand-pick guitar we saw last year.

Even though [Arty Farty Guitars] isn’t sure this hybrid instrument can really be called a Hurdy Gurdy anymore, now that it isn’t using a bowing action, we can’t help but admire the hacking spirit that set him on this journey. We look forward to the promised concert in the upcoming 7th video, once he figures out how to play this thing nicely.

Know of any other hacked-together instruments that possibly should not exist? We’re always listening for tips. 

 

 

 

Ask Hackaday: Are You Wearing 3D Printed Shoes?

July 10, 2025 by 50 Comments

We love 3D printing. We’ll print brackets, brackets for brackets, and brackets to hold other brackets in place. Perhaps even a guilty-pleasure Benchy. But 3D printed shoes? That’s where we start to have questions.

Every few months, someone announces a new line of 3D-printed footwear. Do you really want your next pair of sneakers to come out of a nozzle? Most of the shoes are either limited editions or fail to become very popular.

First World Problem

You might be thinking, “Really? Is this a problem that 3D printing is uniquely situated to solve?” You might assume that this is just some funny designs on some of the 3D model download sites. But no. Adidas, Nike, and Puma have shoes that are at least partially 3D printed. We have to ask why.

We are pretty happy with our shoes just the way that they are. But we will admit, if you insist on getting a perfect fitting shoe, maybe having a scan of your foot and a custom or semi-custom shoe printed is a good idea. Zellerfield lets you scan your feet with your phone, for example. [Stefan] at CNC Kitchen had a look at those in a recent video. The company is also in many partnerships, so when you hear that Hugo Boss, Mallet London, and Sean Watherspoon have a 3D-printed shoe, it might actually be their design from Zellerfield.

Continue reading “Ask Hackaday: Are You Wearing 3D Printed Shoes?” →

A blue 3DBenchy is visible on a small circular plate extending up through a cutout in a flat, reflective surface. Above the Benchy is a roughly triangular metal 3D printer extruder, with a frost-covered ring around the nozzle. A label below the Benchy reads “2 MIN 03 SEC.”

Managing Temperatures For Ultrafast Benchy Printing

July 8, 2025 by 13 Comments

Commercial 3D printers keep getting faster and faster, but we can confidently say that none of them is nearly as fast as [Jan]’s Minuteman printer, so named for its goal of eventually printing a 3DBenchy in less than a minute. The Minuteman uses an air bearing as its print bed, feeds four streams of filament into one printhead for faster extrusion, and in [Jan]’s latest video, printed a Benchy in just over two minutes at much higher quality than previous two-minute Benchies.

[Jan] found that the biggest speed bottleneck was in cooling a layer quickly enough that it would solidify before the printer laid down the next layer. He was able to get his layer speed down to about 0.6-0.4 seconds per layer, but had trouble going beyond that. He was able to improve the quality of his prints, however, by varying the nozzle temperature throughout the print. For this he used [Salim BELAYEL]’s postprocessing script, which increases hotend temperature when volumetric flow rate is high, and decreases it when flow rate is low. This keeps the plastic coming out of the nozzle at an approximately constant temperature. With this, [Jan] could print quite good sub-four and sub-thee minute Benchies, with almost no print degradation from the five-minute version. [Jan] predicts that this will become a standard feature of slicers, and we have to agree that this could help even less speed-obsessed printers.

Now onto less generally-applicable optimizations: [Jan] still needed stronger cooling to get faster prints, so he designed a circular duct that directed a plane of compressed air horizontally toward the nozzle, in the manner of an air knife. This wasn’t quite enough, so he precooled his compressed air with dry ice. This made it both colder and denser, both of which made it a better coolant. The thermal gradient this produced in the print bed seemed to cause it to warp, making bed adhesion inconsistent. However, it did increase build quality, and [Jan]’s confident that he’s made the best two-minute Benchy yet.

If you’re curious about Minuteman’s motion system, we’ve previously looked at how that was built. Of course, it’s also possible to speed up prints by simply adding more extruders.