prusa mk2s fan nozzle

thingiverse

While trying to figure out what to do to improve cooling to possibly prevent overhangs from curling up and knocking over small parts of a difficult model I found this thing: https://www.thingiverse.com/thing:2276997 which supposedly improves cooling by blowing from two sides instead of only from the front. It didn't however quite fit since I have a (homemade) silicone sock on the hot end, so I need more clearance between the nozzles and the hot end. The other dimensions also seemed to be a bit off, at least on my printer, so I decided to make my own (simplified) version from scratch. With the combination of this fan nozzle and extremely low external perimeter speed (10 mm/s) I finally succeeded in printing this https://www.thingiverse.com/thing:2719434 without a brim and 0.15 mm layer height, where even the slightest overhang curling will immediately knock the small parts loose. The nozzle was actually usable printed in PLA, but only for PLA prints and probably not long term. I recommend printing in it ABS anyway. It's a quick and easy print and 30 seconds to swap out the stock fan nozzle so it could be worth trying if your overhangs are causing trouble. It really obstructs the view of what's printing so I'll probably only going to use it when there are difficult overhangs. FreeCAD source included. I'm still trying to figure out how to make robust parameterized models in FreeCAD. This is certainly not perfect, but some of the key dimensions can be tweaked by changing their values in the 'conf' spreadsheet if you want some other compromise between airflow and looks and clearances...