On The Merits Of A Solid-State Dehumidifier Filament Dry Box

March 2, 2024 by Maya Posch 38 Comments

How good are ion membrane dehumidifiers for keeping FDM filament dry and ready for printing? This is the question which [Stefan] at CNC Kitchen sought to answer in a recent video. Like many of us, he was inspired by a video which [Big Clive] made a while ago in which said dehumidifiers were demonstrated for keeping an enclosure free from moisture. Yet would they be able to tackle the much bigger drying job of one or more spools of filament? Thanks to some free samples sent by Rosahl, [Stefan] was able to start answering this question.

Performance of desiccants and dehumidifier element. (Credit CNC Kitchen)

In the experiments, he used the smaller RS1 (€36.25 a piece) for a single spool container, and the larger MDL-3 (€169) with a Bambu Lab AMS multi-spool unit. Normally such an AMS has three big containers with silica desiccant in it that have to be regularly swapped out, but he modified one AMS to only have the big MDL-3 membrane to dehumidify. A second AMS was left with older silica in its containers, and a third got fresh silica, allowing for some benchmarking between the three units.

The results say a lot, with the initial empty AMS test showing the older silica desiccants topping out quickly and leaving the fresh silica and the membrane dehumidifier to go neck to neck. This is not the usual scenario in which you’d use these dehumidification methods of course, and the small-scale test with the RS1 showed that with a full filament spool in the box, humidity inside the container would only drop very gradually as more and more moisture replaced what was removed from the air. In particular the cardboard element of the spool being used was suspected of being one of the biggest sources of moisture.

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3D Printing With Plastic Cutlery

December 25, 2023 by Al Williams 18 Comments

How many plastic spoons, knives, and forks do you think we throw away daily? [Stefan] noted that the compostable type is made from PLA, so why shouldn’t you be able to recycle it into 3D printing stock? How did it work? Check it out in the video below.

[Stefan] already has a nice setup for extruding filament. However, unsurprisingly, it won’t accept spoons and forks directly. A blender didn’t help, so he used an industrial plastic shredder. It reduced the utensils to what looked like coarse dust, which he then dried out. After running it through the extruder, the resulting filament was thin and brittle. [Stefan] speculates the plastic was set up for injection molding, but it at least showed the concept had merit.

In a second attempt, he cut the ground-up utensils with fresh PLA in equal measures. That is, 50% of the mix was recycled, and half was not. That made much more usable filament. So did a different brand of compostable plasticware.

The real test was to take dirty plasticware. This time, he soaked utensils in tomato sauce overnight. He cleaned, dried, and shredded the plastic. This time, he used 20% new PLA and some pigment, as well. We aren’t sure this is worth the effort simply on economics, but if you are committed to recycling, this might be worth your while.

It always seems like it should be easy to extrude filament. Until you try to do it, of course. Recycling plastic bottles is especially popular.

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Four images in as many panes. Top left is a fuchsia bottle with a QR code that only shows up on the smartphone screen held above it. Top right image is A person holding a smartphone over a red wristband. The phone displays a QR code on its screen that it sees but is invisible in the visible wavelengths. Bottom left is a closeup of the red wristband in visible light and the bottom right image is the wristband in IR showing the three QR codes embedded in the object.

Fluorescent Filament Makes Object Identification Easier

August 17, 2023 by Navarre Bartz 14 Comments

QR codes are a handy way to embed information, but they aren’t exactly pretty. New work from MIT’s Computer Science and Artificial Intelligence Laboratory (CSAIL) have a new way to produce high contrast QR codes that are invisible. [PDF]

If this sounds familiar, you may remember CSAILs previous project embedding QR codes into 3D prints via IR-transparent filament. This followup to that research increases the detection of the objects by using an IR-fluorescent filament. Another benefit of this new approach is that while the InfraredTags could be any color you wanted as long as it was black, BrightMarkers can be embedded in objects of any color since the important IR component is embedded in traditional filament instead of the other way around.

One of the more interesting applications is privacy-preserving object detection since the computer vision system only “sees” the fluorescent objects. The example given is marking a box of valuables in a home to be detected by interior cameras without recording the movements of the home’s occupants, but the possibilities certainly don’t end there, especially given the other stated application of tactile interfaces for VR or AR systems.

We’re interested to see if the researchers can figure out how to tune the filament to fluoresce in more colors to increase the information density of the codes. Now, go forth and 3D print a snake with snake in a QR code inside!

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The Effect Of Filament Color On Print Strength And More

February 5, 2023 by Maya Posch 16 Comments

What is an FDM filament coloring’s purpose but to be an aesthetic choice? As it turns out, the additives that create these changes in coloring and transparency also affect the base properties of the polymer, whether it’s PLA, PETG, or another material. This is where a recent video by [CNC Kitchen] is rather illustrative, using a collection of colored PLA filaments from a single filament manufacturer.

[CNC Kitchen] ran a range of tests including tensile strength, ductility, layer adhesion, impact resistance, and annealing performance. The results showed no clear overall winner between plain PLA polymer and any specific color. Perhaps most fascinating was just how much these color additives change the material’s response to annealing. Baking the PLA at 100°C for 30 minutes generally improves material properties, but also can cause warping and shrinking. The effective warping and shrinking differed wildly between the filament.

The general conclusion would seem to be that the natural polymer isn’t necessarily the optimal choice, but that you should test and pick the filament from a specific manufacturer to fit your project’s needs.

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plantpot made from recycled audio tape filament in a 3D printer. Pot contains a succulent plant and is surrounded by tape

3D Printer Filament From Reel-to-Reel Audio Tapes

January 12, 2023 by Dave Walker 18 Comments

At heart, 3D printers are just machines that can melt plastic “wire” into interesting shapes. It’s well-known and oft-lamented that plastic of various sorts has been used to make all manner of household objects that might eventually end up in landfill or otherwise littering the environment. With these facts in mind and a surplus of tape, [brtv-z] decided to see if he could recycle some old reel-to-reel audio tapes into working filament for a 3D printer.

The homebrew rig to convert old audio tape into the unconventional filament

This isn’t the first time he has tried to print with unusual second-hand polymers, back in 2020 he pulled of a similar trick using VHS tape. Through experimentation, it was soon determined that seven strands of quarter-inch tape could be twisted together and fused to form a very tough-looking filament approximately 1.7 mm in diameter, which could then be fed into the unsuspecting printer.

The resulting prints are certainly different in a number of respects from using virgin filament. The material is porous, brittle and (unsurprisingly) rather rusty-looking, but it does have some interesting properties. It retains its magnetism and it catches the light in an unusual way. The video is after the break (in Russian, but YouTube does a reasonable job of generating English captions).

Don’t have any tape handy? No worries, we’ve also covered machines that can recycle plastic waste into filament before. In fact, two of them even won the 2022 Hackaday Prize. What else could you melt down that might otherwise be thrown away?

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New Part Day: Exotic Filament For RF Dielectric Structures

November 20, 2022 by Jenny List 10 Comments

The world of microwave RF design appears to the uninitiated to be full of unimaginably exotic devices, as engineers harness the laws of physics to tame radio signals to their will. Among the weapons in their arsenal are materials of known dielectric properties, from which can be made structures with the desired effects on RF that encounters them. This has traditionally been a difficult and expensive process, but it’s one now made much easier by the availability of 3D printer filaments with a range of known dielectric values.

It’s best to think of the structures which can be designed using these materials as analagous to Fresnel lenses we’re all used to in the light domain. The example piece given by Microwave Journal is a metasurface for use in a steerable antenna, something that would be a much more difficult piece of work by more traditional means.

Normally when we inform you of a new special filament we’d expect it to be more costly than standard PLA, but this filament is in a class of its own at 275 euros per kilogram. So the interest for most readers will probably be more in the technology than the expectation of use, but even then we can see that there will still be microwave experimenters in our range who might be tempted by its unique properties. We look forward to what is developed using it.

Via Microwave Journal. Thanks to [Eric Mockler] for the tip!

ERRF 22: Recreator 3D Turns Trash Into Filament

October 21, 2022 by Tom Nardi 28 Comments

In Back to the Future, Doc Brown returns to 1985 with a version of his DeLorean time machine that has been modified with technology from the future. After telling Marty they need to go on yet another adventure, Doc recharges the DeLorean’s flux capacitor and time circuits by tossing pieces of garbage into the slick Mr. Fusion unit mounted to the rear of the vehicle. The joke being that, in the future, you could simply head over to the local big box store and pick up a kitchen appliance that’s capable of converting waste matter into energy.

Unfortunately, we’re nowhere near powering our homes with banana peels and beer cans. But if the Recreator 3D is any indication, the technology required to turn plastic bottles rescued from the trash into viable PET filament for your 3D printer is all but upon us. While there are still some aspects of the process that could stand to be streamlined, such as fusing multiple runs of filament together into one continuous roll, the core concepts all seem to be in place.

The MK5Kit Mini is currently in development with LDO Motors.

Creator [Josh Taylor] made the trip out to the 2022 East Coast RepRap Festival to not only show off the Recreator 3D, a project he’s been working on now for over a year, but to get people excited about the idea of turning waste plastic into filament. It’s not necessarily a new concept, and in fact [Josh] says earlier efforts such as the PETBOT are what inspired him to create his own open source take on the “pultrusion” concept.

According to [Josh], actually printing with the recycled filament isn’t that different from using commercial PETG, though it’s recommended you lower your speeds. A nozzle temperature of around 260 °C seems to work best, with the bed at 70 °C. Interestingly, the filament produced by the process is actually hollow inside, so the most critical change to make is increasing your extrusion rate to about 130% of normal to compensate for the internal void.

The current revision of the Recreator 3D, known as the MK5Kit, can be assembled using several core components salvaged from a low-cost Ender 3 printer in addition to a number of parts that the user will need to print themselves. For those who’d rather not source the parts, [Josh] says he hopes to get formal kits put together sometime next year, thanks to a partnership with LDO Motors.

But ultimately, [Josh] says the most important thing to him is that the plastic is recycled instead of getting sent to a landfill or incinerator. So whether you build a Recreator 3D or come up with your own design, all are welcome to the PET Pultruders United Facebook group he’s created to discuss the finer points of turning plastic trash into treasure.

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