Five colors of Cast21 on five different wrists.

Cast21 Brings Healing Into 2024

September 14, 2024 by Kristina Panos 16 Comments

It takes but an ill-fated second to break a bone, and several long weeks for it to heal in a cast. And even if you have one of those newfangled fiberglass casts, you still can’t get the thing wet, and it’s gonna be itchy under there because your skin can’t breathe. Isn’t it high time for something better?

Enter Cast21, co-founded by Chief Technical Officer [Jason Troutner], who has been in casts more than 50 times due to sports injuries and surgeries. He teamed up with a biomedical design engineer and an electrical engineer to break the norms associated with traditional casts and design a new solution that addresses their drawbacks.

So, how does it work already? The latticework cast is made from a network of silicone tubes that harden once injected with resin and a catalyst mixture. It takes ten seconds to fill the latticework with resin and three minutes for it to cure, and the whole process is much faster than plaster or fiberglass.

This new cast can be used along with electrical stimulation therapy, which can reduce healing time and prevent muscle atrophy.

Cast21 is not only breathable, it’s also waterproof, meaning no more trash bags on your arm to take a shower. The doctor doesn’t even need a saw to remove it, just cut in two places along the seam. It can even be used as a splint afterward.

It’s great to see advancements in simple medical technologies like the cast. And it looks almost as cool as this 3D-printed exoskeleton cast we saw ten years ago.

Thanks to [Keith Olson] for the tip!

Benchy In A Bottle

August 6, 2024 by Matthew Carlson 20 Comments

Making something enjoyable often requires a clever trick. It could be a way to cut something funny or abuse some peripheral in a way it was never designed for. Especially good tricks have a funny way of coming up again and again. [DERAILED3D] put a 3d printed benchy in a bottle with one of the best tricks 3d printing has.

The trick is stopping the print part way through and tweaking it. You can add manual supports or throw in some PTFE beads to make a generator. The benchy isn’t the print being paused; the bottle is. The benchy is a standard print, and the bottle is clear resin. Once halfway through, they paused the print, and the benchy was left suspended in the bottle with a bit of wire. Of course, [DERAILED3D] moved quickly as they risked a layer line forming on the delicate resin after a minute or two of pausing. The difficulty and mess of tweaking a gooey half-finished resin print is likely why we haven’t seen many attempts at playing with the trick, but we look forward to more clever hacks as it gets easier.

The real magic is in the post-processing of the bottle to make it look as much like glass as possible. It’s a clever modern twist on the old ship in the bottle that we love. Video after the break.

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Keep Your Lungs Clean And Happy With A DIY Supplied-Air Respirator

July 9, 2024 by Dan Maloney 13 Comments

The smell of resin SLA printing is like the weather — everybody complains about it, but nobody does anything about it. At least until now, as [Aris Alder] tackles the problem with an affordable DIY supplied-air respirator.

Now, we know what you’re thinking, anything as critical as breathing is probably best left to the professionals. While we agree in principle, most solutions from reputable companies would cost multiple thousands of dollars to accomplish, making it hard to justify for a home gamer who just doesn’t want to breathe in nasty volatile organic compounds. [Aris] starts the video below with a careful examination of the different available respirator options, concluding that a supplied air respirator (SAR) is the way to go.

His homebrew version consists of an affordable, commercially available plastic hood with a built-in visor. Rather than an expensive oil-free compressor to supply the needed airflow, he sourced a low-cost inline duct fan and placed it outside the work zone to pull in fresh air. Connecting the two is low-cost polyethylene tubing and a couple of 3D printed adapters. This has the advantage of being very lightweight and less likely to yank the hood off your head, and can be replaced in a few seconds when it inevitably punctures.

Another vital part of the kit is a pulse oximeter, which [Aris] uses to make sure he’s getting enough oxygen. His O₂ saturation actually goes up from his baseline when the hood is on and powered up, which bodes well for the system. Every time we pick up the welding torch or angle grinder we wish for something like this, so it might just be time to build one.

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Adaptive Chef’s Knife Provides Better Leverage

May 16, 2024 by Donald Papp 24 Comments

[Colleen] struggled with using a chef’s knife to cut a variety of foods while suffering from arthritis in her wrist and hand. There are knives aimed at people with special needs, but nothing suitable for serious work like [Colleen]’s professional duties in a commercial kitchen.

As a result, the IATP (Illinois Assistive Technology Program) created the Adaptive Chef’s Knife. Unlike existing offerings, it has a high-quality blade and is ergonomically designed so that the user can leverage their forearm while maintaining control.

The handle is durable, stands up to commercial kitchen use, and is molded to the same standards as off-the-shelf knife handles. That means it’s cast from FDA-approved materials and has a clean, non-porous surface. The pattern visible in the handle is a 3D printed “skeleton” over which resin is molded.

Interested? The IATP Maker Program makes assistive devices available to Illinois residents free of charge (though donations in suggested amounts are encouraged for those who can pay) but the plans and directions are freely available to anyone who wishes to roll their own.

Assistive technology doesn’t need to be over-engineered or frankly even maximally efficient in how it addresses a problem. Small changes can be all that’s needed to give people meaningful control over the things in their lives in a healthy way. Some great examples are are this magnetic spoon holder, or simple printed additions to IKEA furnishings.

Hackaday Links: March 24, 2024

March 24, 2024 by Dan Maloney 6 Comments

Way to rub it in, guys. As it turns out, due to family and work obligations we won’t be able to see the next Great American Eclipse, at least not from anywhere near the path of totality, when it sweeps from Mexico into Canada on April 8. And that’s too bad, because compared to the eclipse back in 2017, “Eclipse 2: Solar Boogaloo” is occurring during a much more active phase in the solar cycle, with the potential for some pretty exciting viewing. The sun regularly belches out gigatons of plasma during coronal mass ejections (CMEs), most of which we can’t see with the naked eye because not only is staring at the sun not a great idea, but most of that activity occurs across the disk of the sun, obscuring the view in the background light. But during the eclipse, we — oops, you — might just get lucky enough to have a solar prominence erupt along the limb of the sun that will be visible during totality. The sun has been quite active lately, as reflected by the relatively high sunspot number, so even though it’s an outside chance, it’s certainly more likely than it was in 2017. Good luck out there. Continue reading “Hackaday Links: March 24, 2024” →

Multicolor Resin Prints: Give It A Shot

February 20, 2024 by Al Williams 9 Comments

[Thomas TEMPE] has been making two-color resin prints. While printing in multiple colors is old hat for FDM printers, the way resin printers work makes it a more difficult proposition. [Thomas] has a simple solution. First, he prints an item with a cavity where he would like the second color. Then, after printing, he fills the cavity with a different color resin using a syringe and cures it. Simple, really.

Of course, it is all about technique. For fine lines, you’ll want a smaller needle, and you flood the area with the alternate resin and wipe away the excess. For wider lines, you simply fill the cavity from a larger syringe.

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Make Carbon Fiber Tubes With An Open Source Filament Winder

December 11, 2023 by Maya Posch 21 Comments

Result of winding a carbon fiber tube. (Credit: Andrew Reilley)

Carbon fiber (CF) is an amazing material that provides a lot of strength for very little weight, making it very useful for a lot of applications, ranging from rods in CoreXY 3D printers to model- and full-sized rockets. The model rocketry hobby is the reason why [Andrew Reilley] developed his own CF tube winding machine called Contraption. A tutorial video (also embedded below) shows how this machine is prepped for a winding run, followed by the winding progress and finalizing before admiring the result.

The entire machine’s design with 3D printed parts and off-the-shelf components is open source, as is the TypeScript and NodeJS-based Cyclone software that creates the toolpath specifying the parameters of the tube, including number of layers and the tow angle.

As a wet winding tow machine, the carbon fiber strands are led through the liquid resin before being wound onto the prepared mandrel. During winding some excess resin may have to be removed, and after the winding has been finished the tube is wound with shrink tape. This is followed by a heat gun session to shrink the tape and letting the resin cure. Following curing, the tape and mandrel are removed, resulting in a rather fancy looking CF tube that can find a loving home in a lot of applications, except perhaps ones that involving crushing outside pressures like those found deep below the ocean surface.

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