This is my design for a case for the mainboard of an ender 3 (ender 3/pro/v2). It was created with an SKR e3 v3 in mind, but should work easily with a stock board.
Needed:
6 x 4mm threaded M3 inserts (I used these )
6 x 8mm M3 screws (can reuse ones from original mainboard case)
There is room for a 40x20mm fan, I'm using a noctua 4020 but other brands should fit. There is also 2 little pegs next to the fan enclosure to hold a buck converter if one is needed for the fan.
I've tried to add as much room as possible to route cables, while still ensuring it will fit under the Y axis arm, and the bed spring cogs won't catch on any cables.
once you've got your cables sorted, the lid slides on, and then the entire thing slides back.
When printing, supports are only needed on the right-hand section that fits into the 4040 rail. (and possibly the fan cover, if you struggle with bridging)
The author hasn't provided the model origin yet.