Prusa i3 MK3S Extruder Stepper Cooler Add-on (for 40x40 Fan)

thingiverse

This is a remix of CG-Tech's outstanding extruder stepper motor cooling fan add-on. EDIT: I've uploaded a second version with deflected air ducts, based on CG-Tech's alternative one. It was a quick fix and the stl file is not error-free, but it prints fine via Prusa Slic3r (S3D may spit its dummy though). I tweaked the deflector design a wee bit, so depending on your slicer settings, you should be able to get away without using supports under the deflectors. I've remixed and improved it so that it fits perfectly onto a Prusa MK3S and is held securely in place by the extruder/filament sensor cover screw. I prefer this method to having to glue or tape the part to the outside of the stepper motor and the single screw seems to hold everything pretty tight (but you could add a backup with some tape etc. too, if you encountered any issues with vibration). As designed, the part fits perfectly flush and level with the top of my extruder assembly, but depending on how you built yours, it is possible that you may need to loosen a few screws and realign parts to get everything sitting comfortably. I have also included some cable slots to the rear - one on either side to cater for different brands of fan/different fan orientation. This is best printed using PETG (or ABS/ASA), but you may get away with a decent PLA. You'll need a small amount of localized supports for the two overhangs and also the cover screw hole. I use a black Noctua fan (from Prusa spares) run back to the spare 5V out on the Einsey board, but it'll work with most 40x40 fans. The four fan fixing holes will fit M3 bolts (go for ~5mm longer than the thickness of the fan). Happy printing!