I built a custom case for my computer and needed a way to mount an 80mm case fan without taking up a full 80mm x 80mm area on the outside of the case. With this design, you can mount an 80mm case fan inside your case while only needing 80mm x 40mm of space to create an opening.
The design is broken up into three parts, with only the Fan Top Mount needing supports to print if everything is printed upside down. Please flip the designs 90 degrees to the left as shown by Thingiverse to print in the upside down position.
I separated the Fan Mount Body from the Fan Mount Top to allow ease of assembly when installing the fan and mount inside the case. The Top Grill is separate so you can install a filter screen between the Grill and Mount. I used super glue to secure the grill once I had installed the filter material.
Let me know if you are interested in different sized opening, fan sizes, or angles for the fan and I'll see what I can do.