Prusa I3 MK3 Extruder Motor Fan Duct

thingiverse

The Prusa MK3 is an excellent printer, but direct drive extruders often get extremely warm and the MK3 gets red hot, with temperatures reaching as high as 135 degrees Fahrenheit at the extruder motor. This made it difficult for me to achieve accurate small prints of PLA without the filament becoming mushy in the extruder teeth. To resolve this issue, I designed a custom fan shroud that maximized airflow and heat dissipation. A heat sink was added along with a silent 40mm Noctua fan mounted directly on the extruder motor, as well as a separate 25mm fan to cool the filament and Bondtech extruder. All the hot air is diverted away from the print surface, which helps maintain stable temperatures during sensitive prints. As a result, my extruder temperature has dropped significantly, reaching only 37 degrees Fahrenheit while printing with PETG.