Fan repair (120mm)

If you have a destroyed fan rotor for a 120 mm fan like I did, this model is for you! For the repair, you need to separate the rotor from the rest. You can do that by pushing at the middle of the rotor to separate it from the motor. After that, you need to break all leftover blades off the center rotor. Next, you need to file all leftover stumps flush with the center piece. The last step is to push the new fan blades onto the center piece and reassemble the motor by pushing it back together. It's important to push the new blades the right way around and to clean (and maybe re-lubricate) the motor shaft if it got dirty. After printing the new rotor, you need to remove the support and maybe the thin part of the blade if it came off with the support.

All important measurements are displayed in the pictur (in mm). If they don't fit, you can add some material in the center or cut off material at the blade tips.

Perpormance: 

To ensure the blowing and noise performance, I made sure to consider the original fan speed when choosing the angle of attack and the twist of the blades. I also opted for a higher blade count than the original for increased static pressure (though with slightly less efficiency). The blade shape is different from the original due to printability constraints, but it performs very well. Ultimately, the new rotor matches the old one in airflow and noise. There might be potential improvements from sanding and properly balancing the blades (though this isn't a significant issue with good print quality).

I appreciate any feedback or new ideas.