Folding Robots With Special Materials

When it comes to robots, we usually see some aluminum extrusion, laser-cut parts, maybe some 3D printed parts, and possibly a few Erector sets confabulated into a robot arm. This entry for the Hackaday Prize is anything but. It’s a robot chassis, a 3D printer, and the structural frame for any sort of moving project that’s made out of a special composite material.

[Marc]’s project for the Hackaday Prize is all about articulated mechanisms. Instead of the usual structural components, he’s using Hylite, a special material that’s basically a polypropylene core clad in a sheet of aluminum on both sides. By carefully milling away the aluminum on both sides, [Marc] is creating a living hinge that can be used to build a 3D printer, robot, or really anything else.

This really isn’t a finished project; it’s more of a technology demonstrator. That said, [Marc] has a lot of examples where he can bend these Hylite aluminum plates over on themselves, can create boxes and space frames, and has the ability to create just about any shape he wants. It’s really a highly precise means of bending aluminum with a mill, and has the added benefit of looking really, really good.

Already, [Marc] has a few interesting robots that are built around this construction technology. The first is a remote control focus for a telescope that simply connects an eyepiece to the scope. Actuation is provided pneumatically, and all reports say this example works well. The other example is a flat-pack phone stand. It’s a bit simpler than a focus mechanism, but it is a small and inexpensive way to show off the technology. Great work, and an excellent project in The Hackaday Prize.

16 thoughts on “Folding Robots With Special Materials

  1. Living hinge, what an absurd marketing term. When they die they break apart the lid falls off the catches don’t hold anymore. Dumb. In the trash or r-bin it goes. Real three piece hinges are nearly immortal.

    1. They didn’t invent the term or the concept. On a small scale a living hinge is much more economical and can be more resilient than a three piece hinge. If you’re reading hackaday you probably own several storage bins with living hinges, or if you’ve ever bought tictacs you’ve used them first hand.

    2. Yes when they break they break. That’s the definition of the word – it will not work anymore.

      Will “real three piece hinges” work for this application in the first place?

    3. The durability tests in the project details (14 million cycles total) greatly reduced my concerns about the lifetime of the hinges. I would love to see a test with load until failure though.

      1. If you look at the videos reporting the tests, you will see that after bending the hinge 14 million times, I tried to break it by pulling on it, with a device including a dynamometer. I couldn’t do it because I didn’t foresee the needed force. My system was stalling after 10kgf. As the hinge tested was that of a 3D printer, which is never confronted with such forces, I remained there.

        Why 14 million? Because, after more than a week and a half, I got fed up, that’s all! If I had left the test bench in place, I’m sure it would still torture this unfortunate hinge, today!

    4. Did you actually read anything? It’s tested to 14 million cycles, and it’s way less mass than traditional articulations. It’s not gonna replace all hinges in the world but it’s definitely a useful innovation. Why do people around here advocate old tech so angrily?

    1. Look for “aluminum composite panels.” The same/similar materials are sometimes sold as Dibond or Alumalite. It’s commonly used for signs. US distributors were pricey, but I found some cheap panels on ebay a few years back.

    2. 8020 (the aluminum extrusion folks) sell it as “Alucobest”. It’s 6 mm thick, but you can buy it with an American accent as 0.236″ if you need to. :-) (no, really, same thickness, different catalog numbers!). It’s polyethylene, not polypro tho.

      This is pretty much the same stuff that killed 72 people a year ago today at Grenfell. Watch that fire hazard.

    3. Attention: there are many composite panels (ALUCOBOND, DIBOND, etc.) including a polyethylene (PE) core, and aluminium faces, in thicknesses between 3mm and 8mm.

      Hylite has a thickness of 1.2mm, and it is fundamentally different, because its core is polypropylene (PP). Only polypropylene can make durable hinges. It is a matter of molecular organization in the material.

      If you try to make PE hinges, they will break after a few dozen cycles!

      1. So, Al sheets on the surface are there for rigidity, but endurance in flexing is because of PP ? That’s nice, because nowadays it seems PP is replacing PS in non-foam packaging for food, so it is widely available and can be used to cut out small mechanical parts, flexible linkages, etc. from them. PP thin foil is also ubiquitous as labels on PET soda (and other) bottles, if anyone fancy making their own PP foil capacitors :P, or small electrostatic speakers.

    1. Indeed! My communication for HackaDay is centered on Hylite technology, but most of my work involved a 3D printer, Zatsit. This technology is very suitable for making a 3D delta printer, especially because of the dimensional accuracy and lightness of the mechanism. There are many innovations in Zatsit that have been made possible by the technology used.

      I plan to offer Zatsit on Kickstarter very soon, as a mechanical kit to make a very efficient 3D printer (see http://www.zatsit.fr).

      Translated with http://www.DeepL.com/Translator

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