A fan guard for 40mm fans, which I installed on the Creality Ender 3 with HeroMe mod. HeroMe exposes the fan, so I designed a guard. Does not need screws to install.
Can be used on any other printer with 40mm fan.
Most other guards I saw induced noise or limited the airflow too much.
Main feature here is the guard is well tuned not to cause extra noise or obstruct the airflow in any significant way.
I went through many iterations, you can use whichever you wish, but I suggest the final v8 for optimal results. Also print four of the pins and use superglue to put them on the back of the guard. No screws needed, it holds firmly in the fan holes.
Note that you don't need to download the whole package (especially when going for the last iteration), pick the individual file. For tha v8, I also include a lower poly variant to spare you from unnecessarily huge download (but I personally prefer having absolutely no tiny shiny flat low poly artifacts on my curved prints!).
FreeCAD file included, feel free to remix!
Filament PM (Plasty Mladeč) PETG
Some of the early iterations print without supports, but the airflow is much better and noise lower with some extra clearance from the fan blades. For this, you need supports.