I've been trying to use this to replace a weird Daewoo motherboard's ATX backplate (CB644M-EX, a 440EX chipset Micro ATX board). I've only got PLA filament which I think is less flexible and more brittle than ABS or PETG filaments, however re-reading your post about your blank backplate, I see you rescaled it to account for the thermal expansion of ABS, so it's no wonder I had trouble getting this to fit haha. I designed up one to fit my motherboard based on your scaled up version, printed it out and it wouldn't fit my case at all (at least now I know why...). I ended up snapping off two of the clip sides, so that just fell out of the case after that 😁
I made up the design for the backplate in fusion 360 like so:
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The picture as a template thing sort of works but I think I took the picture a bit too close so it was slightly distorted and ended up 1mm off to the side
I re-designed it a bit by shaving a bit off the edges and re-doing the clip shape to work with my PLA. The clip parts extend outwards a bit higher and are thinner so they're more able to flex. I've also made the clip ridges a bit smaller, which seems to work nicely.
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It took 3 tries to get it to fit, which seems to be a theme with my design stuff - I go through quite a lot of filament right now 😀
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Now it fits nicely in the case, thanks very much!
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I've attached the blank and the Daewoo .stl files & f3d files. They're optimised for printing in PLA at 0.2mm layer height, I've cut the thickness of the backplate down to 0.8mm to cut down on print time, it takes somewhere around 50 minutes right now.