Adding metal screw-eye to cured, printed resin?

It came as a total surprise to me how tough the cured clear resin turned out to be. On prior experiences I’ve had with two-part clear resins, often there was a time when it’d be possible to add a metal screw eye to a charm or ornament., and allow it to then finish the curing process.

I seem to have a Goldilocks dilemma - I don’t want to manhandle and scar the charms while they’re not fully cured, but, I wasn’t able to easily pierce the resin with the screw-eye once it was fully cured. Does anyone have suggestions as to a ‘sweet spot’ timing wise in the curing process when things might be malleable enough? Or, should I simply plan on trying to include a tiny hole where I want the screw-eye to eventually go into the resin, and just treat it as a glued-in-place pin? (I have the feeling that the Formlabs resin isn’t quite strong enough to create a small loop and have it not break off on a charm bracelet during normal movement)

Thoughts, advice?

I definitely say design the hole in place, but not as a slip-in, glue in place fit.

I would think that you would want roughly 50% thread engagement so you don’t overly stress the printed part, you could also throw some liquid resin in the hole before assembly so you don’t have the air visually disrupting your charms. Cure the resin with a laser after assembly and it will look like your hardware is molded in place.

Print some dummy pieces to experimentally find the right size hole.

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That’s a great idea, and I’ll give it a whirl once I figure out a little more about using Fusion 360 / Meshmixer. (I’ve got a lot of learning ahead of me!)

You can heat the part up with a heat gun to soften the plastic then pre drill it and then put your screw into it… Make sure the drill size isn’t too wide, just the diameter of the screw eye - threads.

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