40mm Slotted Fan Cover

Slotted fan cover design for a 40mm x 40mm fan, commonly found as a cooling fan on 3D Printers (ex. Ender 3 Pro).

Features slots arrayed horizontally for an aesthetic look; 1.5mm thick struts spaced 3mm apart. Slots are sunken in on one side to clear fan blades. Screw holes are 32mm spacing.

Includes screw options:

• M4 (Simple)
• M3 (Counter-bored, Simple)
• M2.5 (Counter-bored, Simple)
• M2 (Counter-bored, Simple)

Important note: Adding a cover to the fan will add extra depth to the screw holes, especially on fans that already have counter-bored holes. It is likely that the original screws will no longer reach and need to be replaced with longer ones.

The exact length will vary on what you are screwing into behind the fan, but the cover itself adds 2mm for the counter-bored versions and 4mm for the simple versions. The most common 40mm on printers are 10mm in depth (4010 fans), so you would need a >12mm length screw for counter-bored covers and a >14mm length screw for the simple ones.

Due to the sunken slots on one side of the cover to clear any protruding parts of the fan, all counter-bored screw versions will likely need to be printed face down as an overhangs. Unless you trust your overhangs to be done well, supports will likely be needed (they are pretty small and shouldn't be an issue). This isn't a problem for the simple through-hole versions.

Printed on an Ender 3 Pro: 

- 2-4 Walls

- 10% - 20% Infill, doesn't matter too much since most of the part is walls.

- Supports required: None for simple screw holes, needed for counter-bored holes

- Filament: PLA or PETG