There are 3 significant problems with this design:
Now if we loctite the magnets to the shell there's a zero change of removing them without shattering the magnets, so this is a good solution but we've not nailed down the gluing at scale. Neodymium magnets are so fragile and tiny, it's hard to nail down a good alternative. We tried 3M tape but that was a big nono, things fell of really easily.
- The total machining & threading costs would be very high and we need to use tiny screw (M1 or below) with super flat heads
- The space is very small and it's hard to cram all of the above into it
- More importantly, this creates quite a bit of air between the magnets, leading to significant decrease in pull force (it drops off exponentially with distance and even small separation can reduce the force a lot).
Now something I did notice when re-watching assembly videos is that the factory appears to apply the glue first to more than 1 shell, then fetch and attach the magnets to each of them. I'm not certain what effect this has, but my gut feeling tells me the glue may dry a bit in that time, hence loose some of its effectiveness. When I personally glued the magnets on the pre-production models (which sit rock solid even now) I applied some glue and then squeezed down the magnet right after.
DELO-ML is a great glue for bonding metal parts together. You have to mask or remove the anodizing layer in the glueing area because it's an anaerobic glue which needs metal ions to fully cure. Maybe it's worth a try... that's a very strong glue, also used in the automotive industry.
(Of course, could also try some anaerobic glue from LOCTITE, since DELO is difficult to get in China)
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