Laser-cut Snap-lock Assembly

Here’s a small project featuring what I think is a really nifty snap-lock design for laser cut assemblies. I used it when making dorky headgear for Bay Area Maker Faire 2019.

Dorky head gear (for the record, it feels really awkward to turn my head to the side while trying to look at the camera)

I definitely didn’t come up with this snap-lock mechanism myself. In fact I saw it years ago on the Machines That Make (MtM) project from the MIT Media lab when researching little DIY CNC projects. I liked it so much that it always stuck with me.

The MtM snap locks are cut on thick sheets of plastic using a CNC router, so the parts naturally create stiff square joints. This is less feasible on a laser cutter given the slight draft on all cut edges, but we can overcome this easily by just using two layers of snap lock features, essentially creating a little box structure. While the snap-lock quality is almost certainly superior with the CNC routed parts featured on MtM, the laser cut parts are still pretty nice, and its hard to argue with how fast the process is.

(Funny aside: My good friend Joshua who helped me so much with my laser cutter restoration is currently a grad student working with Prof. Nadya Peek, whose Phd work included MtM Snap!)

close up of the snap-lock feature
parts for silly head gear

The propeller is also a laser cut flat sheet and then just bent by hand, no heat needed even. The “worm gear” is some welding wire bent around a metal rod, which is how I got such consistent “threads.”

same snap lock construction applied to a phone holder on a small camera stand

If you are interested in making your own silly head gear, or modifying these files for your own design, feel free to download the STEP files below:

snap lock v8.step

phone camera stand v3.step

Here’s a quick video of how all these parts go together:






2 responses to “Laser-cut Snap-lock Assembly”

  1. Ben Avatar

    Hi! In your video on the demo board you mentioned that the slide is used for precision locating stage, was wondering how would it be used?

    1. aqian Avatar

      Hi Ben! If you search for “flexure lathe” online, you will find some examples of small lathes where this linear flexure is used to provide X-axis motion. This method doesn’t have any backlash because the springiness of the flexure is always pushing against the screw. It can also be scaled down very small (easily smaller than what might be practical for a lathe). Other examples might be a locating stage for moving a microscope slide around or maybe moving a mirror so that you can very carefully adjust the beam of a laser. Let me know if you have more questions!

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