this post was submitted on 01 Jun 2025
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3D printer toolheads often have large blower fans with big fan ducts ending in small holes and I wonder how necessary that is.

These large part cooling setups are most of the size of the toolhead and significantly reduce print area. Blower fans also do not produce much pressure so those fan ducts greatly reduce their effectiveness.

Does it make sense to, instead of using a blower fan, use a small compressor like for an aquarium and have the airflow delivered Bowden style to a small nozzle? The airflow would be substantially higher than from a fan. Noise isn't really an issue for a tiny compressor.

Has anyone tried this? I might eventually but don't have the time to set it up now.

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[–] j4k3@lemmy.world 4 points 1 month ago

You will find this on many high end ultra fast printers. The compressor makes a lot more noise than a fan.

The Prusa MK3S+ duct is probably the best blower fan design for part cooling. The duct only barely enters the path of the exit from the blower unless the print head is on a flat surface that causes back pressure at the exit. Only then does the air get redirected through the duct in a useful way to get better coverage behind the nozzle.

I took this design and made it snap fit over the end of a blower instead of mounting it to the extruder print head. So I got to know it well.

If you know about the Reynolds number and how length and surface texture impact flow, almost all ducts and fans used in hobby printers are indeed garbage.

Water cooling is so cheap now, we should probably be using it for the extruder. I think the issue with small compressors is duty cycle. Like the ones for refrigerators is super quite but they have a low duty cycle time.