This is a high resolution .stl for a 40mm radial fan. When printed the fan has a diameter of 40mm with a height of 13mm. I attached mine to a motor with a 2mm shaft to test it out.
If you would like to see some alterations made, feel free to post your request under comments.
There are 2 versions of this fan.
Fan.stl is designed to be printed out with "exterior only" support. By doing so it creates support structure underneath the fan blades. The upper ring should come out fine if you have your settings tuned right.
FAN Solid Bottom.stl has a solid bottom plate so that it can be printed without any support.