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 30 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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ERRF 22: Building A Library Of Filament Colors

October 20, 2022 by Tom Nardi 10 Comments

If you’ve ever paged through the color samples at the hardware store trying to match a particular color, you know how hard it can be. Not only are there nearly limitless color variations, but each manufacturer has their own formulas and tints. Often times, the only way to get the exact color you need is to get it custom mixed.

Unfortunately, that’s not really an option when it comes to filament for your 3D printer. Will that roll of orange from Hatchbox actually match the orange from Overture? That’s where the Filament Librarian comes in. Created by [Joe Kaufeld], the project aims to catalog and photograph as many 3D printer filaments as possible so you can see exactly what you’re getting.

Now of course, if it was as easy as looking at pictures of filament swatches on your computer, you wouldn’t need this service to begin with. So what’s the trick? A custom automated camera rig, powered by the Raspberry Pi, is used to position, light, and photograph each filament sample in the library. So while [Joe] can’t promise your monitor is showing a perfect representation of each filament’s color, you can at least be sure they will all look correct in relation to each other. So for example, the site can help you figure out if the local Microcenter stocks anything that comes close to matching Prusament’s Galaxy Silver PLA.

[Joe] brought a collection of his samples along with his slick camera setup to the 2022 East Coast RepRap Festival so attendees could see first-hand how he adds a new filament to the database. With an easy-to-use touch-screen interface, it takes just seconds to get the camera ready for the next shot.

Now that he’s got the hardware and the procedure down, [Joe] is asking the community to help out by providing him with filament samples to process. It doesn’t take much: all he asks is you snip him off a couple meters of filament, write down what it is and who makes it on a pre-made form, and drop it in the mail. If you’re in the US, you can send it directly to his address in Indiana, and for those on the other side of the globe, he’s got a drop point in the Netherlands you can use.

We love a good passion project here at Hackaday, so here’s hoping that the Filament Librarian receives plenty of new filament samples from all over the planet to feed into that fancy camera setup of his.

Vacuum Forming With 3D Printer Filament

December 11, 2021 by Tom Nardi 17 Comments

Even if they don’t have one themselves, we’d wager the average Hackaday reader is at least vaguely aware of how a vacuum former works on a fundamental level. You heat up a plastic sheet until it’s soft, then use a vacuum pump to pull the ductile material down onto an object and hold it there while it cools off. It’s easy to build a vacuum forming rig yourself, but small commercial units are cheap enough that it might not be worth your time. If everything goes to plan, the technique is a quick and effective way of duplicating items around the home and shop.

But we were recently tipped off to a variation of this classic technique that’s certainly worth further research. As demonstrated in a recent video, [Nathan Martinez] shows how 3D printed sheets can be used in place of the 5″ x 5″ squares of thermoplastic film that his imported vacuum former was designed to use. It’s easy enough to do: just model up a square with the appropriate 2D dimensions in your CAD package of choice, and extrude it to a height of about .5 mm.

A printed mesh pattern could be used to form custom shaped filters or strainers.

So what’s the advantage? Well for one thing, it’s cheaper. Though admittedly, not by much. Going rate on Amazon seems to be about 90 cents per sheet for the real stuff, and some back of the envelope math shows the printed version coming in at around 30 cents given nominal filament costs. Whether or not those savings are worth the extra effort is certainly debatable.

But that’s not really the most interesting part. With printed sheets loaded into the vacuum former, you’ve got access to a much wider array of materials to work with. For example, [Nathan] shows off some very interesting flexible pieces he was able to produce using sheets of TPU. You can also experiment with different surface textures. These can not only be used to give your vacuum formed pieces a bit of interesting visual flair, but could actually have some practical applications. In the video we see how a printed mesh could be formed over a piece to create a conformal air vent or filter.

To be sure, there’s some room for improvement here. Not all the pulls were successes, and [Nathan] says getting the printed sheets up to the proper temperature can be tricky. But when it works, it works quite well, and we think there could be some untapped potential in this unexpected melding of new and old methods of at-home plastic production.

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