These fan guards are to be printed clips facing up.
i printed mine in Sunlu black petg at .2 layer height.
Infill shouldn't really matter you can leave it at default.
I used a speed printing input shaping profile.
No supports needed!
Finally i would like to thank Jerry Lee for providing his cad files
The author remixed this model.
Changes from the original:
Added holes for the fan screws.
Increased the clearance for the clips.
Increased the thickness of the shroud.
Added an indentation for the fan so it does not hit the guard.
The top clips were removed for clearance issues.