This design will allow you to mount a 40mm or 50mm fan to the side of the standard QU-BD One/Two Up extruder. The split design will direct air to both the extruder chamber as well as the peek barrel to prevent the filament from softening before entering the peek barrel. Notes: I have not printed the 40mm version Slic3r told me that the design was not waterproof, but it sliced and printed fine My printer is not yet accurate, so you might get better results than me ;) I have added support already, so print without support

Attribution - Creative Commons