spinning thread extruder

Spinning Threads Put The Bite On Filament In This Novel Extruder Design

When it comes to innovation in FDM 3D printing, there doesn’t seem to be much room left to move the needle. Pretty much everything about filament printing has been reduced to practice, with more or less every assembly available off the shelf. Even the business end — the extruder — is so optimized that there’s not much room left for innovation.

Or is there? The way [David Leitner] sees it, there is, which is why he built this rolling-screw extruder (if you can get to the Thingiverse link, [David] cross-posted on reddit, too). Standard extruders work on the pinch-roller principle, where the relatively soft filament is fed past a spring-loaded gear attached to a stepper motor. The stepper rotates the gear, which either advances the filament into or retracts it from the hot end. [David]’s design instead uses a trio of threaded rods mounted between two rings. The rods are at an angle relative to the central axis of the rings, forming a passage that’s just the right size for the filament to fit in. When the rings spin, the threads on the rods engage with the filament, gripping it around its whole circumference and advancing or retracting it depending on which way it’s spinning. The video below shows it working; we have to admit it’s pretty mesmerizing to watch.

[David] himself admits there’s not much advantage to it, perhaps other than a lower tendency to skip since the force is spread over the entire surface of the filament rather than just a small pinch point. Regardless, we like the kind of thinking that leads to something like this, and we’ll bet there are probably unseen benefits to it. And maybe the extruder actually is a place for innovation after all; witness this modular nozzle swapping system.

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Hand-Made Drum Carder Gets Wool Ready For Spinning

Making a natural fiber like wool into something useful like a sweater involves a lot of steps. We might be familiar with shearing the sheep, spinning the wool into yarn, or knitting and weaving, but between shearing and spinning there’s another unfamiliar process you’ll have to go through. Known as carding, it helps align the fibers so they are able to be spun, and of course it requires either an expensive tool, or one you build on your own.

This drum carder is exactly what it sounds like. It uses two drums covered in a metal mesh, spinning at different speeds, which pull the fibers into an orderly shape. Small drum carders like this can run around $600 but with some quality wood and a lathe you can easily make one for a fraction. Making the series of drums is fairly straightforward with a lathe, and from there you need to make sure they are connected with a quality belt or chain and then covered in the appropriate metal mesh.

[kris] notes in the reddit comments section that he’d like for a second version to spin a little faster and be a little more durable, but this is a great working carder nonetheless. From there you’ll want to move on to spinning the wool into yarn, which you can do with either a wheel or an electric motor.

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Keeping Birds At Bay With An Automated Spinning Owl

There’s nothing wrong with building something just to build it, but there’s something especially satisfying about being able to solve a real-world problem with a piece of gear you’ve designed and fabricated. When all the traditional methods to keep birds from roosting on his mother’s property failed, [MNMakerMan] decided to come up with a more persuasive option: a solar powered spinning owl complete with expandable batons.

We imagine the owl isn’t strictly necessary when you’re whacking the birds with a metal bar to begin with, but it does add a nice touch. Perhaps it will even serve to deter some of the less adventurous birds before they get within clobbering distance, which is probably in their best interest. [MNMakerMan] says the rotation speed of the bars seems low enough that he doesn’t think it will do the birds any physical harm, but it’s still got to be fairly unpleasant.

At first glance you might think that this contraption simply spins when the small 10 watt photovoltaic panel next to it catches the sun, but there’s actually a bit more to it than that. Sure he probably could just have it spin constantly whenever the sun is up, but instead [MNMakerMan] is using a ATtiny85 to control the 11 RPM geared DC motor with a IRF540 MOSFET. By adding a DS3231 RTC module into the mix, he’s able to not only accurately control when the spinner begins and ends its bird-busting shift, but implement timed patterns rather than running it the whole time. All of which can of course be fine-tuned by adjusting a couple variables and reflashing the chip.

We’ve seen plenty of automated systems for keeping cats away, and of course squirrels are a common target for such builds as well, but devices to deter birds are considerably less common among these pages. So it would seem that, at least for now, [MNMakerMan] has the market cornered on solar bird smashing gadgets. We’re sure Mom’s very proud.

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Semi-automated Winder Spins Rotors For Motors

What’s your secret evil plan? Are you looking for world domination by building a machine that can truly replicate itself? Or are you just tired of winding motor rotors and other coils by hand? Either way, this automated coil winder is something you’re probably going to need.

We jest in part, but it’s true that closing the loop on self-replicating machines means being able to make things like motors. And for either brushed or brushless motors, that means turning spools of wire into coils of some sort. [Mr Innovative]’s winder uses a 3D-printed tube to spin magnet wire around a rotor core. A stepper motor turns the spinner arm a specified number of times, pausing at the end so the operator can move the wire to make room for the next loop. The rotor then spins to the next position on its own stepper motor, and the winding continues. That manual step needs attention to make this a fully automated system, and we think the tension of the wire needs to be addressed so the windings are a bit tighter. But it’s still a nice start, and it gives us some ideas for related coil-winding projects.

Of course, not every motor needs wound coils. After all, brushless PCB motors with etched coils are a thing.

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Hackaday Prize Entry: Open Source Electrospinning

Electrospinning is the process of dispensing a polymer solution from a nozzle, then applying a very high voltage potential between the nozzle and a collector screen. The result is a very, very fine fiber that is stretched and elongated down to nanometers. Why would anyone want this? These fibers make great filters because of their large surface area. Electrospinning has been cited as an enabling technology for the future of textiles. The reality, though, is that no one really knows how electrospinning is going to become a standard industrial process because it’s so rare. Not many labs are researching electrospinning, to say nothing of industry.

[Douglas Miller] is building his own electrospinning machine. Except for the ominous warning signs on the 40-kilovolt power supply, there’s nothing in this machine that makes it look any different from a normal, homebrew 3D printer. There are stepper motors inside to raise and lower a carriage, a syringe, and a handy USB port. If you didn’t know any better, you could easily assume [Doug]’s OpenESpin is designed to print fidget spinners and tiny tugboats instead of films of carbon nanotubes and piezoelectric thermoplastics.

The DIY electrospinning machine is really what the Hackaday Prize is all about. It’s an enabling technology anyone can build for a few hundred dollars that also allows real science to happen. The films and blobs being formed in [Doug]’s electrospinning machine could easily find a home in a PhD candidate’s thesis or as a component in cutting edge research on everything from battery technology to the Internet of Underpants.

POV Display Does It On The Cheap


[Sholto] hacked together this ultra low-budget spinning display. He calls it a zoetrope, but we think it’s actually an LED based Persistence Of Vision (POV) affair. We’ve seen plenty of POV devices in the past, but this one proves that a hack doesn’t have to be expensive or pretty to work!

The major parts of the POV display were things that [Sholto] had lying around. A couple of candy tins, a simple brushed hobby motor, an Arduino Pro Mini, 7 green LEDs, and an old hall effect sensor were all that were required. Fancy displays might use commercial slip rings to transfer power, but [Sholto] made it work on the cheap!

The two tins provide a base for the display and the negative supply for the Arduino. The tins are soldered together and insulated from the motor, which is hot glued into the lower tin. A paper clip contacts the inside of the lid, making the entire assembly a slip ring for the negative side of the Arduino’s power supply. Some copper braid rubbing on the motor’s metal case forms the positive side.

[Sholto] chose his resistors to slightly overdrive his green LEDs. This makes the display appear brighter in POV use. During normal operation, the LEDs won’t be driven long enough to cause damage. If the software locks up with LEDs on though, all bets are off!

[Sholto] includes software for a pretty darn cool looking “saw wave” demo, and a simple numeric display. With a bit more work this could make a pretty cool POV clock, at least for as long as the motor brushes hold up!

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Spinning-hell Of A Game

North Street Labs really brought their ‘A’ game to the build finals for the Red Bull Creation contest. Behold the Centrifury, their spinning hell of a game. You can’t really make it out (because of the spinning) but the game consists of two bucket seats positioned opposite of each other on a merry-go-round type deck. Each player has a button in front of them which must be held down for the rig to start spinning. When you can’t take it any more just release the button and the spinning will stop. But you’ll also have lost the game. Whomever can hold out longer wins.

It’s not surprising to see such a well-polished build. After all, this is the same group that built the violently vibrating game of Simon. This time around most of the work came in the form of engineering and welding. First they had to make sure the design could take the forces this things puts out, then they had to build it. And all within the 72-hour time limit. We’re not sure what’s harder, winning the game or trying not to smile while watching the video after the break.

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