This is a remix of my original active cooling fan design. The original design is still in use and has been used continuously for the past 2 years.
This design replaces the fan bracket with one where the fan slides in from the top to be held securely.
Note: this design is for a 40x40x20mm fan, where the original design was for a 40x40x10mm fan.
I used 3 perimeters, 4 top layers, and 3 bottom layers.