What is a quieter alternative to 50mm blower fan for part cooling?

Hello everybody.

For some time I have been printing with a 50mm blower fan for part cooling but I'd really like to put something more silent. The noctua fans have caught my eye as a silent solution but they seem to have a lot less air displacement compared to the usual 50mm blower. The fan that I have currently has 25 CFM (according to aliexpress data) which translates to 42 m3/h.

My question is if anybody has a suggestion about a quieter alternative to 50mm blower fan for part cooling?
Alternatively, if anybody has ever calculated the minimum air flow required for decent part cooling? With that I will be able to figure out how big of a noctua fan can give me adequate cooling results.

Best

Just put a potmeter in series to the fan or use PWM to let it run quieter. A lot cheaper than buying expensive "silent" fans and you can always crank it up if needed.

Fans make noise because of blade speed. The efficiency of the blade also affects it, but even the cheap fans tend to have fairly efficient blades.

So, you can either slow the fan down, thereby reducing the blade speed and noise, or you can go to a larger fan, which spins much slower to move the same amount of air.

For "decent cooling" there are a huge number of variables, including the air temperature, the part temperature, and how efficiently the material transfers heat to the air. The last is the hardest, since it varies not just by material, but can also depend on the colour of the material you're printing. that's before we even get to whatever your definition of "decent" cooling is.

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MBot3D Printer
MakerBot clone Kit from Amazon
Added heated bed.

Leadscrew self-built printer (in progress)
Duet Wifi, Precision Piezo parts

My bad...by decent I mean effective. Hopefully that makes my point more clear.

Thanks for the opinions. I shall experiment on!

Best

I use a set of fans that have a combined output of 2.2 cfm (1.1 cfm each) and can still print in PLA with good overhangs. I have a small duct on them with an opening around 10mm wide

DJdemonD and co sell them on their site -- https://www.precisionpiezo.co.uk/product-page/sunon-blower-radial-fan-5v
out of stock at the moment, but I'm sure we can convince him to get some more... I know I'd buy again!


I took quite a bit of time to choose these fans. A lot of low output fans have awful designs, such as the more commonly available 40x40mm blower fan (such as this). The blades protrude out of the case and cause a loss of pressure and output when ducted, or at least that's my theory.

However, these small fans are not quiet! it seems the answer to quieter fans is to make them bigger, or run at a lower pwm. Whatever you do though, 25cfm is certainly overkill.

Thank you Origamib. I will bear that in mind...now i at least know the ballpark. I'm curious about your setup though...whats your experience with cooling from opposing sides? I've read that they pretty much cancel each other out, never experimented myself though.

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Thank you Origamib. I will bear that in mind...now i at least know the ballpark. I'm curious about your setup though...what's your experience with cooling from opposing sides? I've read that they pretty much cancel each other out, never experimented myself though.

I'm not sure. People who say they know are most likely talking out their butt... take it all with a pinch of salt. It's very hard to know what micro air flows are doing at the best of times.

BUT, I think in my set up they do not cancel each other out. They are angled down, not directly at each other and if you follow the path directly out of the nozzle, the air flows do not converge until about 7mm below the nozzle. This means that the print will always be the first thing the air flow hits, not another airflow in the opposing direction.



My personal experience is that even with high airflow, you still get problems with directional cooling -- One side will always be worse at overhangs then the other. With my setup, you still get *some* overhang problems at the front and back of the nozzle where the fans are not positioned, but it is drastically less then a 1 fan set up. In fact, I sought out the micro air coolers because after experiencing direction cooling problems I used 2x 50mm blowers which made my gantry look ridiculous and was not space efficient. Most of my overhang problems now exist at the back of the nozzle due to heat build up around the back of the heat block and only when I print single small items.

For example, it recently became a problem for me when I printed Christmas baubles in vase mode that were only 30mm across. This is not really a cooling issue though as heat build up around the heat block is inevitable but can be avoided by printing faster, Z hopping, printing multiple items etc (anything that stops the nozzle staying in one spot too long). I do also use a silicone sock.

In regards to high airflow vs low airflow though, they both have their compromises. Low airflow must be efficiently directed at the areas you want to cool, whereas high airflow can be blasted everywhere much easier to give the necessary cooling -- This can cause adhesion issues on the bed where the airflow hits a print wall or weird print geometry and is directed straight onto the bed instead or thermal runaway issues in your hotend.

Edited 3 time(s). Last edit at 12/13/2017 03:51PM by Origamib.

Interesting that this topic came up just as new stock of fans arrived. The 30mm blowers are in if anyone wants them. See my sig.

Out of interest, I use them unducted and again slightly off centre to one another. I have no complaints, although I mainly print ABS where cooling is less critical.

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Simon Khoury

Co-founder of [www.precisionpiezo.co.uk] Accurate, repeatable, versatile Z-Probes
Published:Inventions

I have the 40mm blower on mine, 12v but the build quality doesnt look as good as the 30mm ones how cute are they , the 40mm design has more different blades, very light, but cover panel comes off easy, bit of glue will do the trick but its on at mo without it. they seem quiet to me, and so far have performed fine even without directional bit...though I think bridging with .1mm layers might show up a flaw in my thinking, but my part warping seems fine now.

Edited 2 time(s). Last edit at 12/16/2017 12:34PM by MechaBits.