3D printed in-place mechanisms and flexures, such as living hinges, are really neat when you can get them to print correctly. But how do you actually do that? YouTuber [Slant 3D] is here with a helpful video demonstrating the different kinds of springs and hinges (Video, embedded below) that can be printed reliably, and discusses some common pitfalls and areas to concentrate upon.
Living hinges are everywhere and have been used at least as long as humans have been around. The principle is simple enough; join two sections to move with a thinned section of material that, in small sections, is flexible enough to distort a few times without breaking off. The key section is “a few times”, as all materials will eventually fail due to overworking. However, if this thing is just a cheap plastic case around a low-cost product, that may not be a huge concern. The video shows a few ways to extend flexibility, such as spreading the bending load across multiple flexure elements to reduce the wear of individual parts, but that comes at the cost of compactness.
Moving on from springs, the second part of the video describes a few strategies for print-in-place hinges, describing how they fail, and what to do to mitigate. Again, robustness comes at a cost, in this case, increased bulk, but with 3D printing, you get what you pay for. Overall, it’s a nice, concise guide to the topic and well worth a mere seventeen minutes of your time, we reckon.
We see 3D printed flexure mechanisms a lot ’round here, like this for example. But how precise are they? Finally, we think this 3D printed spherical flexure joystick is cool, but must have been a bit tricky to model!
Thanks to [Hari Wiguna] for the tip!
3D printing flexures and living hinges is such a cool challenge! Slant 3D’s video does a great job breaking down the process and pointing out common pitfalls. It’s amazing how small adjustments can make such a big difference in durability. If you’re into 3D printing, this is a must-watch!
(Just keep saying to yourself, “that’s NOT Rob McElhenney”)
Great article on exciting capabilities of 3D printing! My only disagreement is with your comment about coil springs. While it is true that FDM is not a good process for coil springs, powder based SLS works great. When ever possible, we print the spring as a connected integral part with the mechanism. BDS
Slant 3d has a series of videos where he basically yells at his customers for designing things “incorrectly” and making his life more difficult. It’s quite cringe inducing – but in a can’t-look-away sort of way. He also claims that 3d printing will take over injection molding soon. Yet he had to stop making his line of branded filimate becuase he couldn’t source the plastic spools for shipping. It’s all very odd.