Comment by IgorPartola | Hacker News Reader

Comment by IgorPartola | Hacker News Reader

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I have a 3D printer I bought a few years ago and I keep it in my office. It was quite loud as is and I sent through the process of quieting it down. Fans were a big part of it. It has four of them: power supply, main board, and two on the hot end/extruder. Noctua was what was mostly recommended, but (a) price and (b) at the time I believe they mostly or only had 12 volt fans and this printer ran on 24V so each fan would need a voltage converter board.

Well turns out you can get quieter and cheaper fans on e.g. Mouser or Newark that are 24V compatible. They let you sort and filter by size, voltage, noise level, and volume per minute so I found the quietest possible fans that still move roughly the same volume of air as the stock ones. The price was half to a quarter of equivalent Noctua fans (excluding converters) at that time.

From what I hear (pun intended) Noctua makes a great product both functionally and aesthetically, but don’t overlook industrial suppliers either.

Did you also stat out the static pressure? It's an important factor I don't see you mention and a lot of people over look it. It's especially important on some of those fans because the ducting and cooling they're pushing has restrictions and need a fair amount of static pressure to maintain the rated CF/M. Quieter fans generally have a lower static pressure rating too so you might not be getting the CFM you think for fans like the part cooling fan that has to push the air through the ducting around the head.

I don’t remember if I did but I can tell you that the performance I am getting from them is more than adequate. Cooling has not been an issue at all which I can measure and continuously monitor for some of these with the printer’s built in sensors. Basically for something like this use case the point isn’t to make it as cool as possible but cool enough to work correctly which these fans are more than able to do all day long at a volume level that is inaudible to me.

they said "volume per minute" so, yes, they were getting the CFM they wanted

CFM is not a static value it depends on the 'load' applied to the fan, a fan with no restrictions will have higher CFM than the same fan facing no restrictions and the relationship between the CFM and the static pressure depends on the fan design. Low static pressure fans can't push air effectively through tubes or restrictions and the flow volume (CFM) drops because it cannot push the air on the output hard enough to flow. High SP fans usually have larger more closely spaced blades so that the air cannot escape back through the fan.

For example on radiators you need higher static pressure fans to push the air through the small space between the fins on the radiator, if you use a high CFM fan with low mm H2O (static pressure) the fan doesn't actually manage to push the rated CFM through the radiator. Same for ducting you see in 3DP applications.

CFM is a measure of volume moved, generally quoted at effectively zero static pressure. Zero static pressure is rarely reality. All fans will have a static pressure vs airflow curve, which will vary based on the design of the fan.

I doubt normal people have the tools to measure fan CFM, especially when mounted into a product or enclosure, so presumably the OP was going based on stated specs.

On top of that low static pressure fans are generally quieter so if dB and CFM were their main criteria they probably didn't get the correct fans which is why I asked.

>From what I hear (pun intended) Noctua makes a great product both functionally and aesthetically

Can confirm. I was unaware of the large difference in different fans that weren't priced far apart previous to a Noctua recommendation. After hearing them in situ beside some other brands it is incredible the difference in sound. I strictly use them on my homelab and the spinning hard-drives make more noise than the fans.

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