Mellow Fly-DP5 DIN rail mount

I wanted a mount for the Mellow Fly-DP5 mainboard that matched the style of the mounts used in the Ender 3 NG project. I wasn't sure how much clearance would be required for the stepper drivers, so I decided that I'd use some M3 standoffs that I have on-hand in various sizes instead of modelling the standoffs into the fan mounts and requiring overlong screws for them. In practice the TMC2209 drivers that I'm using are no taller than 25mm even with their heatsinks installed, so 25mm M3 standoffs should be fine.

Two of the Ender 3 NG generic rail mounts ("electronics_din_rail_generic_mount.stl") are required for attaching to the DIN rail; these are attached with M3 x 8mm screws that cut their own threads into the plastic of the generic mount. 

Four Ender 3 NG heatset inserts are used to make it easier to mount and dismount the mainboard; I used M3 x 35mm metal standoffs to install the mainboard on the mount - if you're intending to use the second “extruder” driver then use 3 standoffs, and an M3 x 10mm screw in the mounting hole in the top left of the board, because the heatsink won't fit on the leftmost driver if a standoff is used there. Otherwise, if you're intending only to use 4 drivers then 4 stands will work well, since the default configuration is to use the drivers from right to left.

Atop the standoffs I've installed a mount for an 80mm 24V fan; the fan is installed onto the bracket via PC fan screws through from the rear, while the mount screws into the standoffs with M3 x 14mm screws. 14mm worked for me, but the tapped length of the standoffs does vary so find a length that works for you.

As an alternate I've included a mount for a pair of 40x0 fans. I'm not sure what will end up being most suitable but I've printed both to try out.