3d Printer hacks

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[Ben] at workbench with 3D-printed sea scooter

Watertight And Wireless In One Go: The DIY Sea Scooter

August 11, 2025 by 26 Comments

To every gadget, tool, or toy, you can reasonably think: ‘Sure I could buy this… but can I make it myself?’ And that’s where [Ben] decided he could, and got to work. On a sea scooter, to be exact.

This sea scooter was to be a fully waterproof, hermetically sealed 3D-printed underwater personal propulsion device, with the extreme constraint that the entire hull and mechanical interfaces are printed in one go. No post-printing holes for shafts, connectors, or seals. It also meant [Ben] needed to embed all electronics, motor, magnetic gearbox, custom battery pack, wireless charging, and non-contact magnetic control system inside the print during the actual print process.

As [Ben] explains, both Bluetooth and WiFi ranges are laughable once underwater. He elegantly solves this with a reed-switch-based magnetic control system. The non-contact magnetic drive avoids shaft penetrations entirely. Power comes from a custom 8S LiFePO₄ pack, charged wirelessly through the hull. Lastly, everything’s wrapped in epoxy to make it as watertight as a real submarine.

The whole trick of ‘print-in-place’ is that [Ben] pauses the builder mid-print, and drops in each subsystem like a secret ingredient. Continuing, he tweaks the printer’s Z-offset, and onwards it goes. It’s tense, high-stakes work; a 14-hour print where one nozzle crash means binning hundreds of dollars’ worth of embedded components.

Still, [Ben] took the chance, and delivered a cool, fully packed and fully working sea scooter. Comment below to discuss the possibilities of building one yourself.

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The Trials Of Trying To Build An Automatic Filament Changer

August 11, 2025 by 17 Comments

Running out of filament mid-print is a surefire way to ruin your parts and waste a lot of time. [LayerLab] was sick of having this problem, and so sought to find a proper solution. Unfortunately, between off-the-shelf solutions and homebrew attempts, he was unable to solve the problem to his satisfaction.

[LayerLab] had a simple desire. He wanted his printer to swap to a second spool of filament when the first one runs out, without ruining or otherwise marring the print. It sounds simple, but the reality is more complicated. As an Australian, he couldn’t access anything from InfinityFlow, so he first attempted to use the “auto refill” features included on the Bambu Labs AMS 2. However, it would routinely make filament changes in outside wall areas of a print, leaving unsightly marks and producing poorer quality parts.

His next effort was to use the Wisepro Auto Refill Filament Buffer. It’s a feeder device that takes filament from two spools, and starts feeding the backup spool in to your printer when the primary spool runs out. Unfortunately, [LayerLab] had a cavalcade of issues with the device. It would routinely feed from the secondary spool when there was still primary filament available, jamming the device, and it didn’t come with a proper mounting solution to work with consumer printers. It also had bearings popping out the top of the housing. Attempts to rework the device into a larger twin-spool rig helped somewhat, but ultimately the unreliability of the Wisepro when changing from one spool to another meant it wasn’t fit for purpose. Its feeder motors were also to trigger the filament snag cutters that [LayerLab] had included in his design.

Ultimately, the problem remains unsolved for [LayerLab]. They learned a lot along the way, mostly about what not to do, but they’re still hunting for a viable automatic filament changer solution that suits their needs. Filament sensors help, but can only do so much. If you reckon you know the answer, or a good way forward, share your thoughts in the comments. Video after the break.

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How To Design 3D-Printed Parts With Tolerance In Mind

August 4, 2025 by 12 Comments

One of the continuing struggles with FDM printing is making sure that parts that should fit together actually do. While adding significant tolerance between parts is an option, often you want to have a friction fit or at least a gap that you cannot drive a truck through. In a video by [Slant 3D] a number of tips and tricks to improve parts design with tolerance in mind are provided.

Starting with the fairly obvious, such as avoiding sharp corners, rounding off edges and using chamfered edges  and filets for e.g. lids to make getting started easy, the video then moves into more advanced topics. Material shrinkage is a concern, which is where using thin walls instead of solid blocks of material helps, as does using an appropriate infill type. Another interesting idea is to use a compliant mechanism in the lid to get a friction fit without getting all print parameters just right.

On the opposing side to the lid – or equivalent part – you’d follow many of the same tips, with the addition of e.g. slots that allow for the part to flex somewhat. All of this helps to deal with any variability between prints, with the suggested grip fins at the end of the video being probably the most extreme.

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Open Source 5-Axis Printer Has Its Own Slicer

August 4, 2025 by 22 Comments

Three-axis 3D printing has been with us long enough that everybody knows the limitations, but so far, adding extra axes has been very much a niche endeavor. [Daniel] at Fractal Robotics wants to change that, with the Fractal 5 Pro 5-axis printer, and its corresponding Fractal Cortex slicer.

The printer looks like an extra-beefy Voron from a distance, which is no surprise as [Daniel] admits to taking heavy inspiration from the Voron Trident. The Fractal 5 shares a core-XY geometry with the Voron, using beefy 30 mm x 30 mm extrusions. Also like the Voron, it runs Klipper on a Raspberry Pi hiding in the base. Under a standard-looking printhead using a BondTech extruder and E3D volcano hotend, we find the extra two axes hiding under the circular build plate. The B axis is a gantry that can pivot the build plate assembly a full 90 degrees; the A axis spins the plate without limit thanks to the slip rings built into the design.

The extruder may look fairly normal, but it has actually been designed very carefully to allow the nozzle to get as close as possible to the build plate when the B-axis is at 90 degrees. It looks like the E3D hotend is actually the limiting factor there, which gives plenty of design freedom when planning prints in the accompanying Fractal Cortex slicer.

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Squishy Beyblades Made With 3D Printer Fail To Compete In The Arena

August 2, 2025 by 7 Comments

When Beyblades first came out a couple of decades ago, they quickly became a fad across Japan and several Western countries. There was a whole ecosystem of parts that you could buy and use to build competitive fighting spinning tops. These days, though — 3D printers are ubiquitous. There’s very little stopping you from printing whatever Beyblade-compatible parts your heart desires, as [JettKuso] demonstrates.

For [JettKuso], the rubber attack tips were a personal favorite. They had high grip on the plastic arena floor and would allow a top to make rapid, aggressive moves that would knock other tops out of the arena. Not desiring to import specific Beyblade parts at great expense, he decided to print some rubber tips and associated parts instead. The result? Squishy Beyblades!

[JettKuso] built various tops with official and custom TPU parts, and put them in battles to see what worked and what didn’t. In many cases, the TPU replacement parts didn’t make a big difference or proved worse than the standard parts. However, when [JettKuso] got crazy, he found one thing that kind of worked. A mega-heavy TPU top blade, which weighed as much as the standard metal rings, was able to successfully win battles against less competitive standard builds.

Ultimately, the video serves as a testament to the developers of the original toys themselves. It’s not so simple to just print up some parts and have them be competitive with the tried-and-tested gear that comes off the store shelves. The experience ultimately gave [JettKuso] a greater appreciation for all the thought that went into the commercial toys. Video after the break.

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A filament extruder is shown on a workbench. On the front is a knob and the display of a PID controller. A black geared spool is mounted on the top of the extruder, and on the right, a clear plastic bottle is positioned over a metal rod.

Turning Waste Plastic Into Spools Of Filament

August 1, 2025 by 28 Comments

Despite being a readily-available source of useful plastic, massive numbers of disposable bottles go to waste every day. To remedy this problem (or take advantage of this situation, depending on your perspective) [Igor Tylman] created the PETmachine, an extruder to make 3D printer filament from PET plastic bottles.

The design of the extruder is fairly standard for such machines: a knife mounted to the frame slices the bottle into one long strip, which feeds through a heated extruder onto a spool which pulls the plastic strand through the system. This design stands out, though, in its documentation and ease of assembly. The detailed assembly guides, diagrams, and the lack of crimped or soldered connections all make it evident that this was designed to be built in a classroom. The filament produced is of respectable quality: 1.75 mm diameter, usually within a tolerance of 0.05 mm, as long as the extruder’s temperature and the spool’s speed were properly calibrated. However, printing with the filament does require an all-metal hotend capable of 270 ℃, and a dual-drive extruder is recommended.

One issue with the extruder is that each bottle only produces a short strand of filament, which isn’t sufficient for printing larger objects. Thus, [Igor] also created a filament welder and a spooling machine. The welder uses an induction coil to heat up a steel tube, inside of which the ends of the filament sections are pressed together to create a bond. The filament winder, for its part, can wind with adjustable speed and tension, and uses a moving guide to distribute the filament evenly across the spool, avoiding tangles.

If you’re interested in this kind of extruder, we’ve covered a number of similar designs in the past. The variety of filament welders, however, is a bit more limited.

Thanks to [RomanMal] for the tip!

Stephen Hawes operating his LumenPnP

The LumenPnP Pasting Utility: Never Buy Solder Stencils Again?

July 30, 2025 by 11 Comments

Over on his YouTube channel the vivacious [Stephen Hawes] tells us that we never need to buy solder stencils again!

A big claim! And he is quick to admit that his printed solder paste isn’t presently quite as precise as solder stencils, but he is reporting good success with his technique so far.

[Stephen] found that he could print PCBs with his fiber laser, populate his boards with his LumenPnP, and reflow with his oven, but… what about paste? [Stephen] tried making stencils, and in his words: “it sucked!” So he asked himself: what if he didn’t need a stencil? He built a Gerber processing, G-code generating, machine-vision implemented… website. The LumenPnP Pasting Utility: https://paste.opulo.io/

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