The filament stepper motor on the UP3D Mini gets VERY hot and when using PLA the heat can cause the stepper motor gear which feed the filament to the nozzle to start slipping and this can lead to a stripped gear on the feeder mechanism.
I made this cooler to fit around the motor on the two sides visable. I fixed a small heatsink onto the side facing the door and used heatsink fixing strip around the edges of this device to glue it firmly to the motor.
The fan is 40mm and available with the heatsink at Maplins locally for a few pounds.
The Fan sucks in cold air from the 'chimney' across the motor and heatsink blowing out towards the door of the printer which can be left open. The 12 volt supply for the motor was taken from the plug which supplies power to the original fan on the other side of the print head with no problems.
The fan mounting is sufficiently distant from the stepper motor to prevent any magnetic conflicts which would cause it to stop.
The cooling effect is excellent.
One simple STL file. Print it on it's side, chimney down to save plastic.
Here is a link for the heat sink and fan that I used:-
I stuck the heatsink directly onto the motor casing just behind the fan.
If you need any further information, I will be most happy to assist you, just let me know.