3D Prints That Fold Themselves

3D printing technologies have come a long way, not only in terms of machine construction and affordability but also in the availability of the diverse range of different printing materials at our disposal. The common consumer might already be familiar with the usual PLA, ABS but there are other more exotic offerings such as PVA based dissolvable filaments and even carbon fiber and wood infused materials. Researchers at MIT allude to yet another possibility in a paper titled “3D-Printed Self-Folding Electronics” also dubbed the “Peel and Go” material.

The crux of the publication is the ability to print structures that are ultimately intended to be intricately folded, in a more convenient planar arrangement. As the material is taken off the build platform it immediately starts to morph into the intended shape. The key to this behavior is the use of a special polymer as a filler for joint-like structures, made out of more traditional but flexible filament. This special polymer, rather atypically, expands after printing serving almost like a muscle to contort the printed joint.

Existing filaments that can achieve similar results, albeit after some manual post-processing such as immersion in water or exposure to heat are not ideal for electronic circuits. The researchers focus on this new materials potential use in manufacturing electronic circuits and sensors for the ever miniaturizing consumer electronics.

If you want to experiment printing extremely intricate structures, check out how [_primoz_] brilliant technique revolutionized how the 3D printing community prints thin fibers, bristles, and lion sculptures.

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Polyurethane, Meet 3D Printing

3D printing makes prototyping wonderful. But what do you do when your plastics of choice just aren’t strong enough? For [Michael Memeteau], the answer was to combine the strength of a vacuum-poured polyurethane part with the ease of 3D-printed molds. The write-up is a fantastic walk through of a particular problem and all of the false steps along the way to a solution.

The prototype is a connected scale for LPG canisters, so the frame would have to support 80 kg and survive an outdoor environment. Lego or MDF lattice were considered and abandoned as options early on. 3D printing at 100% infill might have worked, but because of the frame’s size, it would have to be assembled in pieces and took far too long anyway.

The next approach was to make a mold with the 3D printer and pour the chosen polyurethane resin in, but a simple hollow mold didn’t work because the polyurethane heats as it cures. The combined weight and heat deformed the PLA mold. Worse, their polyurethane of choice was viscous and cured too quickly.

The solution, in the end, was a PET filament that deforms less with heat, clever choice of internal support structures to hold the stress in while being permeable, and finally pouring the polyurethane in a vacuum bag to help it fill and degas. The 3D-printed hull is part of the final product, but the strength comes from the polyurethane.

Mold-making is one of the killer apps of 3D printing. We’ve seen 3D prints used as molds for spin-casting hollow parts, and used as a sacrificial shell for otherwise epoxy parts. But for really complex shapes, strength, and ease of fabrication, we have to say that [Michael]’s approach looks promising.

3D Printing T-Shirt Designs

Usually, t-shirt designs are screen printed, but that’s so old school. You have to make the silkscreen and then rub paint all over – it’s clearly a technique meant for the past. Well, fear not, as [RCLifeOn] is here to bring us to the future with 3D Printed T-Shirt Designs.

[RCLifeOn] affixes t-shirts to his print build platform and boom: you’ve got 3D printed graphics. He started by using PLA which, while it looked great, wasn’t up to a tussle with a washing machine. However, he quickly moved on to NinjaFlex which fended much better in a wash cycle. While the NinjaFlex washed better, [RCLifeOn] did have some issues getting the NinjaFlex to adhere to the t-shirt. With a little persistence and some settings tweaking, he was able to come out ahead with a durable and aesthetically pleasing result.

Now, 3D printing isn’t going to replace screen printing, but it’s also not going to replace injection molding. What 3D printing lacks in speed and efficiency, it makes up in setup time & cost. In other words, if you need 50 t-shirts of the same design, screen printing is the way to go. But, if you need 50 shirts, each with a different design, you just might want to follow in [RCLifeOn’s] footsteps.

Anyways, we don’t have much on 3D printing t-shirts, but we do have other useful information on 3D printing slinkys and 3D printing project enclosures. And, if you’d rather do it the old-school way, we can show you how to silkscreen all the things.

3D Printing With Yarn and Silicone

This one is apparently a few years old, but the idea looks so good that we’re left wondering whatever happened to it.

[Seyi Sosanya] made what amounts to a 3D printer, but one that prints in a unique way: wrapping yarn around pillars and then post-dipping them in a silicone glue. The result is a tough, flexible 3D mesh that’s lightweight and looks fairly resilient. We’re not at all sure what it’s good for, but watching the video about the project (embedded below) makes us want to try our hand at this sort of thing.

So what happened? Where did this project go? Is anyone else working on a glue-plus-fabric style printer? Is anyone doing this with carbon fiber and epoxy? We can also imagine that with the right adhesive this could be used less like a loom and more like a traditional FDM machine, although weaving the layers together may provide additional strength in what would be the Z direction, and for that you’d need the supports.

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Collider Prints Hollow Shells, Fills Them

3D printing is full of innovations made by small firms who’ve tweaked the same basic ideas just a little bit, but come up with radically different outcomes. Collider, a small startup based in Chattanooga TN, is producing a DLP resin printer that prints hollow molds and then fills them.

colliderThat’s really all there is to it. The Orchid machine prints a thin shell using a photocuring resin, and uses this shell as the mold for various two-part thermoset materials: think epoxies, urethanes, and silicones. The part cures and the shell is dissolved away, leaving a solid molded part with the material properties that you chose.

This is a great idea for a couple of reasons. DLP-based resin printers can have very fine features, but they’re slow as dirt when a lot of surface area needs to be cured. By making thin-walled molds, this stage can go faster. The types of UV-curing resins out there for use in resin printers is limited by the need to photo-cure, while the spectrum of two-part plastic materials is much broader. Finally, resin printers are great for printing single topologically-simple objects, and molds are essentially just vases.

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The 3D-Printed Mutoscope You’ve Always Wanted

[John] got his hands on a 3D printer, and did what any hacker with a new toy would, printed himself a Mutoscope. (A what?) A Mutoscope is an early flip-book based motion picture machine, and in this case it displays 24 frames from “A Clockwork Orange”. [John]’s 3D-printed machine is, not coincidentally we assume, printed in orange plastic.

The model for the frame is up on Thingiverse, but there’s not all that much to it, honestly. It’s a frame and a few wheels that hold some skewers in place. The rest of the work is making the flaps.

But getting to the end product wasn’t a straight walk. [John] describes all of the starts and stops in his blog, aptly named “Fail Try Again”. We like seeing the whole process rather than just the final, seventh, iteration of the device.

Where to take this project next? We want to see a design with a mounting bracket for a cheap stepper motor built in. We’ve always wanted our own custom signage, and there’s nothing cooler than the flap-flap-flap noise that flip book pages make when being switched. We must not be alone in thinking so, because we’ve seen two beautiful DIY builds in the last two years: this one done in multiples for advertising purposes and this one done just for the lulz. [John]’s project is a lot simpler, and thus a lot more accessible. We hope it inspires a few of you to make your own.

Direct To Object 3D Printing

As the patents for fused-filament 3D printers began to expire back in 2013, hackers and makers across the globe started making 3D objects in their garages, workshops and hackerspaces. Entire industries and businesses have sprung up from the desktop 3D printing revolution, and ushered in a new era for the do-it-yourself community. Over the past couple of years, hackers have been pushing the limits of the technology by working with ever more exotic filament materials and exploring novel and innovative ways to make multi-colored 3D prints. One of the areas lagging behind the revolution, however, is finishing the 3D print into a final product. We’d be willing to bet a four meter reel of 5 V three-and-a-half amp NeoPixels that there are just as many artists and craftsman using 3D printers as there are traditional hackers and makers. These brave souls are currently forced to use the caveman technique of paint-and-brush in order to apply color to their print. We at Hackaday hereby declare this unacceptable.

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