Continously Extruding 3D Printed Tubes With Compressed Air

August 9, 2026 by Aaron Beckendorf 3 Comments

[Jan] of [Roetz 4.0] has a unique approach to multi-material 3D printing: he’s designed an extruder which takes two different materials and extrudes one as a shell around the other. This opens up some interesting possibilities, such as a conductive filament surrounded by an insulating shell; [Jan], however, didn’t have an immediate use for the process, so he moved on to a related technique: extruding plastic tubes with a compressed-air core.

The extruder he used for this was a variation on the dual-material extruder; it takes in two strands of filament, melts them, and extrudes them as a shell around the outlet of a compressed-air line, which was controlled by a high-precision pressure regulator. During testing with PLA, it seemed capable of extruding airtight tubes of filament, though it had a tendency to blow bubbles and form tubes with inconsistent diameters. The low thermal conductivity of the stainless steel extruder also proved problematic; coupled with the cooling effect of the compressed air, filament sometimes solidified inside the extruder.

[Jan] found it almost impossible to get consistent results using only pressure-based control; as the layer of molten plastic around the air gets thinner, it provides less resistance to further ballooning, leading to continuous expansion until the bubble bursts. Controlling the volume of air extruded provided much more consistent results, and in a second video, he built a peristaltic pump to do just that. He also switched to using TPU filament, which greatly improved layer adhesion. When inflated with compressed air, the finished TPU structures expanded slightly, though there were still air leaks. The results look promising, and TU Darmstadt has already carried out some research in this area.

In a separate research project, we’ve seen a similar multi-material co-extrusion approach used to print pneumatic channels. For more on the history of [Jan]’s multi-filament extruder, check out his Minuteman printer. Continue reading “Continously Extruding 3D Printed Tubes With Compressed Air” →

A man's hands are shown holding a broken 3D-printed hook. The hook has a loop and hook, in a number 9-shape. The hook portion has broken, exposing carbon fibers.

Strengthening 3D Prints With A Carbon-Fiber Epidermis

August 4, 2026 by Aaron Beckendorf 10 Comments

As strong and light as carbon fiber-epoxy composites are, the same can’t always be said of carbon-fiber reinforced 3D printer filaments. Of those that do improve over stock filament, the best performance comes from long, continuous strands, but the printers that can embed these are quite expensive. [MagicLAG], looking for a cheaper method, made something even stronger: prints reinforced with subsurface carbon-fiber cloth.

They tried a few other methods first, including pausing the print and manually embedding carbon fiber strands, ironing strands into the finished part, and ironing carbon fiber cloth into the bottom layer. For the main method, though, he printed the test part in three pieces: a core part, and two outer shell layers. Between the core and the shell is a small gap, into which carbon-fiber cloth can be epoxied. Under good conditions (not using quick-setting epoxy), this mostly preserves the outer surface and dimensional accuracy.

To test the various strengthening methods, [MagicLAG] printed hooks and tensioned them on a load cell until failure. None of the methods using single-stranded fiber showed any improvement; the fiber simply bent and let the surrounding plastic break. As a control for the epidermal cloth parts, they printed shells and cores and epoxied them together. These controls performed better than the standard parts, but not nearly as well as the carbon-fiber cloth composites. With only a few layers of cloth, these more than tripled the yield strength of the basic hook.

If you’d rather use a carbon-fiber filament, the type of plastic matters; carbon fiber makes PLA, at least, weaker. Regardless of form, some caution is called for whenever handling carbon fiber, since it seems to show some asbestos-like effects.

Commercialization And Innovation

August 1, 2026 by Elliot Williams 17 Comments

The last year or two has seen relatively affordable multi-material printers hit the market, and the question that [Tom Nardi] and I were kicking around when he was writing up the 2025 year-in-review article was what it was going to mean for our folks. I don’t think he got it wrong per se, but his heading for that section “Grandma is 3D-Printing in Color” only tells half the story.

He did get that part right, though. We’ve certainly seen a flourishing of multi-material designs out there that take advantage of the availability of (usually) four colors. The ability to print in color has given life to the purely decorative models, of course. Think full-color Pokemon desktop toys, for instance. But even functional prints have benefited from contrasting color labels printed right into the box, not to even mention the multi-material supports that pull off easier and cleaner than ever before.

Since most of these multi-filament machines are pretty much locked down as far as hardware tinkering goes, our sights were firmly locked on what the end-user would do with the new capability. But we overlooked the third axis of 3D printering: the software hackers. And it’s precisely in this area of slicer and path-planning that we’ve seen some of the coolest developments this year. Why? Because people have the hardware in their hands that they need to test out the algorithms.

FullSpectrum and the more recent ImageMap are two techniques to get the missing in-between colors out of a four-filament printer, and in particular ImageMap tries to get the job done faster, and with fewer purges. We are amazed to see two different approaches to color blending popping up in just a few months of each other, and we have no doubt that work on this is going to continue.

At the end of the day, this really is just “put new tools in the hands of creative hackers, and they’ll find new ways to use them”, so we shouldn’t have been surprised at all. But if this is what comes out of the commercialization of the multi-material printer, what’s going to come when some of the more esoteric machine designs go mainstream? We can’t wait to find out!

An owl printed with detailed color patterns

New Method Accelerates Color 3D Printing

July 23, 2026 by Julian Scheffers 35 Comments

Multi-color 3D printing is notorious for being difficult to get right. Even with modern printers, you often end up using much more filament (and tool changes) than you would for a single-color print. [YKG3D] shows us a new method of color printing that needs far fewer tool changes. It’s the work of [SentientStardust] and you can check it out here.

Based on 2018 research, the new slicer rotates through its palette of colors each layer. Then, either by adjusting the amount of filament dispensed or by displacing the edges, the prominence of each color is adjusted. The result is smoother gradients and better color blending — and it prints faster too!

Of course, nothing is perfect: the more base colors you add, the thicker your apparent layer lines will be. For example, a 3-color print with 0.2 mm layer height will appear as having 0.6 mm layer height. A different issue happens when the walls get too steep; the color blending illusion starts to break down.

Continue reading “New Method Accelerates Color 3D Printing” →

Giving Resin 3D Printers Another Shot After Six Years

July 21, 2026 by Maya Posch 26 Comments

My initial experience with a 3D printer came in 2020, when I got access to a buddy’s Creality LD-002R SLA printer. This was one of those awkward transition phases for SLA printers, where inefficient RGB LCDs finally got replaced by monochrome LCD panels, thus massively reducing the required exposure time and increasing the LCD panel’s lifespan.

The closely related Creality LD-002H is a monochrome SLA printer, but as this wasn’t the one that this friend opted for we had to learn the ropes on this more old-school printer. In terms of specifications this meant a build volume of 119 mm x 65 mm x 160 mm to play with and a claimed 26.1 µm resolution. Despite some struggles along the way, this machine churned out impressively high levels of detail with whatever cheap resin we threw at it, and even the post-printing processing became easy once we added a flex plate to the build plate and tweaked the cleaning and curing steps.

Despite all these positives, we both drifted away from resin printing, mostly due to the still messy and smelly printing process. FDM printers seemed like a better deal, especially after said buddy got his mittens on a used IDEX FDM printer. I would eventually go through a rather loathsome Creality Ender V2 experience before ending up with my current-day Elegoo Neptune 4, and resin printing seemed to be a thing of the past for me. Until recently, that is.

Continue reading “Giving Resin 3D Printers Another Shot After Six Years” →

Seven Ways To Install Magnets Into Your 3D Prints

July 19, 2026 by Maya Posch 12 Comments

Magnets are awesome, so it’s no wonder we love to add them to our 3D prints. Doing so in a way that will actually last is harder, with thermal creep being one reason a simple friction fit will loosen over time, and using super glue to hold a magnet in place can be messy. In a recent video, [Slant 3D] covers seven ways to install magnets in 3D prints without resorting to glue, along with the advantages and disadvantages of each.

With friction, the argument is that you can still use them, but you’d want to use something like cylindrical magnets rather than flat magnets to increase the friction with the thermoplastic. Using an arbor press rather than human primate hand power is also beneficial.

Rather than installing magnets halfway through a print with all the logistics that entails, you can use side slots to install said magnet into, which is much easier, but as with all embedded magnets, you get that plastic barrier between the magnet and its target.

Other methods involve using a bit of extra material that you need to push the magnet past, using something like an arbor press, so the magnets should never just fall out. A wildcard here: spherical magnets, which can be locked in using a similar method, while automatically orienting themselves to an opposing magnet.

The final tip is to never use two magnets in a magnetic lock. Instead, use a cheaper ball bearing or a similar plain metal part on one side instead. Magnets tend to be much more brittle than whatever stainless steel ball bearing or washer you can use on the other side.

Of course, people will always try to install magnets during an FDM print, but before they try to do that anyway, they really should learn about the fascinating ways in which magnets can ruin print beds, destroy nozzles, and otherwise make a total mess of a print. Magnets seem magical. Maybe they are.

Continue reading “Seven Ways To Install Magnets Into Your 3D Prints” →

Automated Pressure Advance Using A Bed-Leveling Sensor

July 19, 2026 by Maya Posch 8 Comments

One of the most crucial aspects of FDM 3D printing is ensuring sufficient material is extruded. Determining the right flow rate can be done manually, but some printers these days automatically perform this adjustment, which is very convenient. [Stefan] of CNC Kitchen investigates how to add similar functionality using existing bed-leveling sensors.

A major complication with extrusion in FDM printers is that the flow rate has to fit the printing speed. However, you can’t just immediately speed up or reduce the flow rate, as the melting filament is flexible and thus acts like a spring, especially as the extruder is exerting significant force on the filament, which adds compression.

The moment you reduce or increase the speed of the nozzle, you can get over- or under-extrusion, but the delayed response by the extruded filament means that you have to adjust for this change in advance. Ergo, the name ‘pressure advance’, also known as the K-value. Obviously, this is a parameter that differs with each material, printer, and other factors, so a direct measurement is always the best.

In the Bambu Lab X1 FDM printer, a Lidar scanner was used to scan various test patterns to automatically determine the optimal setting. This was later moved to the purge section of the extruder in newer Bambu Lab printers. On other FDM printers, the only available sensor in that area is typically the pressure sensor for bed leveling. Could this sensor make a similar measurement?

This wasn’t just an idle thought, but was inspired by the Snapmaker U1, which runs open-source Klipper, with tantalizing glimpses of how it does pressure-advance sensing in its extruder. This extruder also only contains a load cell, as do some Prusa printers. These much more open printers thus provided a test bed for some experimentation.

With load cell data available, [Stefan] measured how various extrusion rates affect the load cell, which can then theoretically be correlated with the appropriate K-values for specific transitions. He created a calibration tool for a range of Prusa printers that works with stock firmware, though this is definitely still a work in progress. There are also a couple of similar open-source projects, such as this Auto PA Calibration project by [Mark].

Overall, K-value presets tend to work pretty well, but adding a pressure-advance calibration feature to existing FDM printers is definitely an interesting idea. There’s also the prospect of lateral sensing using this same bed-leveling sensor, which could allow the printer to sense much more than just the bed.

Continue reading “Automated Pressure Advance Using A Bed-Leveling Sensor” →