Mendel90 x-carriage hotend fan duct (always on, for hexagon hotend)

thingiverse

I am designing a small printed fan duct for the hexagon hotend, an all-metal hotend that requires a constantly running fan for cooling its heatsink. On my Mendel90 3D printer, I've installed this fan duct on the left side of the x-carriage between the rods, where it stays secure without requiring any modifications to the carriage itself - simply drill one 3mm hole in it, and you're good to go. From there, use an M3 screw from above to fasten the duct into place. A nut trap within the duct ensures a snug hold on this screw. To get everything set up properly, make sure to tilt the stl model before slicing or printing. The duct itself will be printed standing upright on the fan mounting bracket. As soon as your print is complete, carefully remove the support structure at the intake end of the duct - that thin strip was just there to help guide it in place. I'm using a 40mm 12V fan, one that comes bundled with the hexagon kit, and so far it's been working out fantastic for my printer. The cool air stream stays quite close to the hotend without picking up any of its heat; not even PLA extrusion can upset the airflow - a huge win! I've also installed the nozzle fan duct, another crucial piece for optimizing this print job. This fan duct pairs seamlessly with my other 90/360 open Mendel90 nozzle fan duct, which itself is designed specifically to work with hexagon hotends. Take note of that little cutout on top of the fan duct: that's intentionally left open so your extruder still has clear access when you're setting it up. If printing proves tricky, don't worry - a slow pace and adequate cooling should keep things going smoothly; any uneven areas will end up under the x-carriage when all is said and done. When you do print, I find that two layers of perimeter with 25% infill in PLA yields pretty great results for this design. Remove that temporary support frame inside the fan inlet carefully once your piece is done. Mount a sturdy 40mm 12V fan right onto the duct - those holes are for M3 screws, by the way - but don't forget: this hexagon hotend always needs its constant air circulation going over the heatsink fins. If you do encounter trouble during assembly or disassembly of the duct, no worries at all! No need to remove your extruder from the carriage just yet - use a longer screwdriver to handle the situation nicely and neatly. And one final word: for operating your 3D printer successfully with this setup in place, be sure to keep that fan running consistently whenever you're printing away! The hexagon hotend is highly sensitive to changes in air flow - especially around those heat transfer areas. So remember: cool steady airflow across the heatsink at all times!