A basic mini print-in-place triangular box. I mainly made this as a prototype for some similar prints that I want to make eventually for personal use, but it is a fully functional (albeit small) box for those who want it. Feel free to reference it, modify it, resize it, etc.

To print, the back of the box (with the axle and the box cover) should be on the bottom when slicing, such that the front of the box (opposite the axle) is facing up. The model is designed to be printed and function as one piece, although you may need to apply a bit of force to remove/break the supports inside to get it to work. If you've ever printed a Flexi print, the post-printing process is similar to those.

testcase_v4 - Working version.
testbox_v5 - Added handle and slightly extended box cover to fit better (assuming nothing weird happened). I don't have a clue if this works or not because I haven't printed it, so use with caution. Main reason I modified it is I need to use it in a different model for something else.

I don't plan on changing the model further, since this is a prototype after all. That being said, I'd recommend anyone who wants to actually use it to add a handle to the box cover and potentially lengthen the cover a bit to make it align seamlessly with the bottom of the box when closed.

Prusa

i3 MK2.5

No

Yes

0.1 mm

10%

Basically the above settings, although supports were set to only be on the print bed. I haven't actually tried no supports yet, so it might work with those. The only place supports were generated for me was on the ~70 degree overhang between the back of the box and the axle, but I imagine a lot of printers could handle it (mine isn't fully tuned yet though). To make the print-in-place work, the print should be oriented so that the back (with the axle + box cover) is on the bottom.

After printing, the important thing is to get supports out. Namely, the supports on the back of the box between the axle and the box wall need to be removed for the model to work. After that, turn the cover forwards (toward its closed position), applying a bit of force (though not enough to break the model). This should break the supports inside the axle holes and allow the axle to rotate freely. If the print still doesn't work, it's possible there was some mistake made in either the slicing or the printing.

The mechanism isn't particularly complex, though it was a bit annoying to model since everything's really small. It's basically just an axle that fits into holes on the box walls, keeping the axle in place but allowing it to rotate freely. It's the same general idea behind the hinges on Flexi models (the articulated flexible ones everywhere on Thingiverse), albeit a bit different in implementation.