Bukoschnozzle Circular Fan Duct

by buildrob, published

Bukoschnozzle Circular Fan Duct by buildrob Apr 4, 2013


A PLA cooling fan duct for a Bukobot with a Bukoschnozzle hot end and initial X-carriage version (with plastic printed linear bearing holders rather than the new all metal design). It should work with either a Vanilla/Green or Duo and with either version of the Bukoschnozzle wooden hot-end insulator design.

One of my design goals for this fan was that it had to be unobtrusive and so it mounts up underneath the X carriage between the two steel rods. This does mean that the top of the fan intake is partially obstructed by the rear linear bearing but that seemed a small price to pay.

Things I changed from the original design by Ahasuerus:

  • increase size so that it fits 50mm fan instead of 40mm
  • increase size of the center space to allow for the larger Bukoschnozzle heater block (ID now 33mm)
  • cut out an area on the topside to allow the duct to clear the x-carriage linear bearing holders
  • slightly increase relative aperture of fan outlet by ~20% (to increase air flow)
  • rake inwards the outside annulus edge to increase visibility of printed parts underneath
  • add a mounting arm to allow fan duct to be attached to the x-carriage using a cable tie
  • removed indentation on one side of air funnel from original model

I have uploaded a second (larger) version of the fan duct which has a internal diameter which is 4mm larger (37mm). This gives more clearance between the hot end and the duct or allows you to position the nozzle closer to the center.

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Holy cow, that's awesome! Great job on that!

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  • Bukobot with Bukoschnozzle hot end and older x-carriage design
  • Good insulation around hot end. I didn't allow very much clearance between the hot end and fan duct so either you need good insulation so that the duct doesn't melt or print it in ABS (you want good insulation anyway due to the increase airflow around the nozzle). Some ideas here: http://bukobot.com/hot-end-thermal-management You can also use the larger version if your insulation isn't as good.
  • A 50x50x10mm 12V fan with around 10-11 CFM airflow
  • Some cable ties.
  • Two M3 screws which are 16-20mm in length and two M3 nuts (although cable ties could also potentially be used to attach the fan to the duct)


  1. Print it.
  2. Install it. If you are worried about vibration against the x-carriage then you could use a small ball of Blutac on top of the unattached top corner although I haven't seen any problems here - the cable tie holds it quite securely. If the fan duct hole doesn't line up with your hot end you may need to loosen your hot-end mounting bolts and move the hot end further back.
  3. Wire it up. See here for some pointers: http://bukobot.com/pla-print-cooling-fan to allow the firmware to control the fan speed.
  4. Enable cooling in your slicer profiles. You don't want to run the fan at 100% all the time as this can cause extra stringing. For the majority of printing it should either be off or run at a low speed - most slicers support this.

Holy cow, that's awesome! Great job on that!