Description

This is a case for small glasses. It was inspired by living hinge designs meant for laser-cut plywood. However, I wanted to experiment with arrays of 3D-printed print-in-place rigid hinges.

https://youtu.be/ut0pfMXIyXI

Printing

STL files should be oriented correctly so that the proper side is on the print bed.

If printing the cross-section reference, the use of a brim is recommended.

Do not use brim or supports for the glasses case or mechanical test.

Tested to work with PLA and PETG.

When releasing from the bed, avoid applying too much to the living hinges used for the latches.

Parts Required

• M2-4mm hex socket screws
  • x2
• M2 hex nuts
  • x2
• Chamois glasses cleaning cloth

Tools required

• M2 hex socket driver (Allen wrench or compatible Torx wrench)
• Pliers
  • Optional: I could usually press fit nuts with my fingers (phrasing?)

Assembly

See the first part of the video for more details.

1. Break off the modelled-in supports from the edges (if they didn't already break off when released from the bed).
2. On the track teeth, there are two seats (one on each side) for M2 nuts. Press fit the nuts into the seats.
3. Roll the tracks into the wheel so the nuts are in the wheel and line up with the wheel bores.
4. Thread in the M2-4 screws. Some overhangs may block the bores, so feel free to stick something in to remove the overhang and clear the bores.
5. Place the chamois cloth in the case.
6. Finish rolling the rest of the track onto the wheel and press the latches into place.

Caveats

• The glasses case has a small carrying capacity. Do not assume this will fit your glasses unless you've checked with the reference print.
• The glasses case is not designed for heavy-duty protection or protection against violent forces. I make no guarantees on this design. Use good judgment in protecting your eyewear.
• No idea if/how-much the living hinge will degrade over long-term use, but long storage in hot environments probably doesn't help.

Notes

Because the parts of the print on the bed are the case's exterior, this is a good opportunity to use a textured or holographic print bed.

A reference gauge is included that represents the cross-section of the case's container. This can be used to check if glasses will fit in the case by threading them. If glasses can thread through but touch multiple edges of the reference, it's probably too big, as crushing forces may bend the case and transfer those forces onto your glasses.

A shorter version of the case model is included as a demo and print test. At 15% infill with default slicer print settings, it's about 1/3 the print time and plastic. This can be used to check how successfully your printer would print the mechanisms and features.

This is a work in progress because I may revisit the loose hinges later.