I am having a lot of troubles with running my Prusa Mk3S at my student dorm, because of the extremely loud stock part cooling fan - it annoys people A LOT). So I started working on a design using one or two Noctua 40x20 axial fans (2 to get more static pressure) as part cooling fans.

So I wanted to ask if it/they would provide sufficient cooling to replace the centrifugal fan currently on the extruder assembly. Does anyone have some experience on these kinds of builds?

  • 3
    $\begingroup$ Noctua fans run slower to make less noise, so the flow is limited. What do you mean by using 2 fans, is this parellel or consecutive? E.g. these fans have a ridiculously low static pressure rise that is doesn't make sense to stack them. $\endgroup$
    – 0scar
    Apr 11, 2023 at 10:59
  • $\begingroup$ Thanks for the advice! I was thinking about using two on parallel, to push more air volume. Does that tmake sense? $\endgroup$
    – Caeleste
    Apr 11, 2023 at 13:19

1 Answer 1


This probably does not make sense.

Noctua fans are quiet because they're really low-flow, and aside from really high-power (and noisy!) models like 4028 server fans, axial fans in general are unsuitable for part cooling because they have essentially no static pressure, meaning you can't run them through narrowing ducts. If you can just mount them to blow directly where you need the air, without a duct compressing it at all, they might work, but this tends to lead to a bulky toolhead that collides with ends of the axis, reducing your build volume, or that's cantilevered in ways that subjects the whole toolhead to vibrations.

I would look for a quieter radial blower fan that meets your needs. Note that the high quality dual-ball-bearing fans are generally a lot noisier than the garbage sleeve-bearing ones; the advantage is that the bearings don't wear out after a year or so. But if your goal is minimizing noise, you might do best to just buy new sleeve-bearing fans when they wear out. Knowing Prusa, they probably put the high quality fans on there, which would be why they make more noise.


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