Extruder fan specification ?  

Re: Extruder fan specification ?

Hello,

my prusa i3 mk2 arrived today, so i'm looking forward to assemble it. i will change the bearings and i read alot about the fan.

i already ordered this one: http://www.tonisport.de/marken/muchmore/39734/muchmore-turbo-cooling-fan-30x30x10mm?c=4274 which should be capable of moving 9.50 CFM±15% air.

these are the specifications: http://www.muchmoreracing.net/product_view.php?pidx=1327

maybe this helps or i get told that this isn't working at all 🙂

bye
Marco

Re: Extruder fan specification ?

I was doing some research about fans and static pressure and have found something that looks promising. In theory it should boost fan's static pressure. I 'm using stock 30 mm fan, therefore cannot test it. Maybe someone would like to give it a try and share results with us? 😉

https://pinshape.com/items/31510-3d-printed-pc-fan-pressure-boost-adapter-40x40x10mm
http://www.thingiverse.com/thing:432630 - free one

Re: Extruder fan specification ?

???

http://www.thingiverse.com/thing:2211780

Thomas

Re: Extruder fan specification ?

I let go my aerodynamic almost 20yrs already, so correct me if I made mistake.

http://www.thingiverse.com/thing:2211780
This is for intake, to reduce the drag on intake airflow, faster air sucked into fan = more intake airflow = more exit airflow.

https://pinshape.com/items/31510-3d-printed-pc-fan-pressure-boost-adapter-40x40x10mm
This is for exit, act similar to stator vanes (static blade which doesn't rotate) in jet engine's compressor stage, which increase pressure.

http://www.thingiverse.com/thing:432630
And this is also for exit, but not really for increase pressure but reduce turbulence of exit air, which will make air travel further. You can see such design on living room air circulator.

To optimize the design you basically need to customize based on blade/rpm etc and look at the application/requirement. It's good for student to study on but not for me...

I would "guess" strator-vanes-like will do better on our application since we basically are forcing air from 43mm dia into 33mm dia, and then with bunch of heatsink fin behind. Higher pressure "probably" do better for such.

Re: Extruder fan specification ?

I'd tried to use Laminar Flow Fan Plate ( http://www.thingiverse.com/thing:432630 ) with Tilted Adapter ( http://www.thingiverse.com/thing:2076234 ) together.

Add Laminar Flow Fan Plate in between fan and adapter will improved cooling. I didn't measure how long it will for cooling down from 210'c to 55'c, but it's so obvious that you need to run PID tune in order to get temperature right.

This is my PID tuned result:

Without Laminar Flow Fan Plate: P19.90 I1.34 D73.75
With Laminar Flow Fan Plate: P22.39 I1.59 D78.89

Re: Extruder fan specification ?

On at related tangent, I made an air duct for the part cooling fan on front to keep the intake air away from hot sources (somewhat). Give it a try and let me know how it goes. Print in PLA so the dimensions fit since ABS can shrink.

http://www.thingiverse.com/thing:2251648

Re: Extruder fan specification ?

On at related tangent, I made an air duct for the part cooling fan on front to keep the intake air away from hot sources (somewhat). Give it a try and let me know how it goes. Print in PLA so the dimensions fit since ABS can shrink.

http://www.thingiverse.com/thing:2251648

I understand the idea and why you made it, but doesn't this actually make the fan even louder now? Kind of like a Phonograph?

Re: Extruder fan specification ?

---I understand the idea and why you made it, but doesn't this actually make the fan even louder now? Kind of like a Phonograph?
🙄 about the "Phonograph" interpretation: it would make the fan sensed as louder, if it was located at the at the smaller end of the funnel.
➡ in fact the fan itself wouldn't be louder, but you would notice it as louder because of the better impedance matching to the auditory space.... (but explaining this in detail would require a full lecture in acoustics).

💡 the idea of using a slightly bigger fan and a funnel should reduce the noise notable. the small 30x30mm fan needs to shovel about 4 cubic-feet of air per minute to cool down the coldend, which is quite a lot for the tiny fan.
to shovel the same amount of air through the duct, the bigger fan simply doesn't need to spin as fast as the tiny one and the turbulences at the edges of the fins (they generate the most noise) are much smaller.

don't know if using the laminar fan plate really is sufficient at our extruder body (because of the lamellas of the coldend cooler).
but titus.o's experience shows at least that the pid values have changed. but from this you can't conclude a better or even worse cooling behaviour.

Re: Extruder fan specification ?

while searching fans I came across this http://www.ebay.fr/itm/201076953894 stupidly epensive around £25 usually but at €6 I thought i'd give it a try. not as quiet at 25db as the noctua for sure , but way better than the 30db of the std 30x30 fan and at 5.2 cfm and static pressure of 41mm good specs too. i'll report back with a cooldown test once it arrives

Re: Extruder fan specification ?

😳 sorry @jon.m: didn't realized that you've answered to jltx's funnel to provide "clean air" to the fan. thought you were refering to titus.o's post.

🙄 can't edit my previous post anymore, so i've to agree to your "phonograph" interpretation of jltx's funnel with this additional post !

@all: discard my posting above, based on a misinterpretation of jon.m's post 😕

Re: Extruder fan specification ?

I was wondering if a kind of "silencer" like this one would be efficient too.

http://www.thingiverse.com/thing:2284893

I'm a bit concerned by dust accumulation through ...

Re: Extruder fan specification ?

Well the San Ace fan arrived..it's not as utterly silent as the noctua but its a big improvement on the 30x30 fan for sure, just printing a PLA item and I'll time the cooldown time .. very happy and even just with my fingers by the pinda sensor I can feel the increased airflow compared to the noctua..

and christophe.p how you gonna mount an exhaust fan that size on the outlet side from the heatsink? The pinda sensor and it's wires are completely in the way?

Re: Extruder fan specification ?

Well, obviously it would need some adjustment (resise for 30 mm fan, dig some room for Z thread, room for the 4 screws ...), or maybe modifying existing one with additionnal part to potentially reduce noise.

I was wondering what guys expert in fan noise here would think of that.

Dust accumulation would be a challenge as well.

Re: Extruder fan specification ?

OK some results.. i never ran a test with the original 30x30 fan , i might refit it at some point just to run a baseline but with the 40x40x10 san ace 109P0412M702 which has VERY similar specs as the original fan, slightly more cfm a fraction less static pressure but not much.. I used two different adapters to test first this one http://www.thingiverse.com/thing:2076234which we'll call A. then this one https://grabcad.com/library/mk2_40mm_fan_duct-1 which we'll call B . it was incidentally a sod to print, found after a number of failed attempts that turning it on its side and adding custom supports in simplify3d worked best.
A.
0min 200º
1min 162º
2min 136º
3min 114º
4min 97º
5min 83
6min 72º
7min 63º
8min 56º
9min 50º
9.05g stop

B.
0min 200º
1min 160º
2min 132º
3min 109º
4min 93º
5min 79º
6min 68º
7min 59º
8min 52º
8.09 stop

so the B. adapter alone got me a 1minute improvement in cooling time..and BOTH are faster than the noctua which was around 9.15 cooldown time total so I'm happy with my setup. comparable to original with lower sound.. it's not a completely silent as the noctua but at the end of the day to get more airflow and especially static pressure the fan blades MUST spin faster. Its that simple. almost all the "silent" fans turn between 3500 and 4500 rpm.. same fans "non silent" run at between 5500 and 6500 rpm..so long as there's no actual mechanical noise from the fans you hear the air moving, can't do much about that.

Re: Extruder fan specification ?

As I am reading and realizing that Noctua 40x40x10 fan is not very "good" I was wondering if anybody knows about EBM-Papst fans? These are said to also be very silent and robust, being used for industrial applications.

http://www.ebmpapst.com/en/products/compact-fans/axial-compact-fans/axial_compact_fans_detail.php?pID=53733
http://www.ebmpapst.com/en/products/compact-fans/axial-compact-fans/axial_compact_fans_detail.php?pID=120053
http://www.ebmpapst.com/en/products/compact-fans/axial-compact-fans/axial_compact_fans_detail.php?pID=53735
http://www.ebmpapst.com/en/products/compact-fans/axial-compact-fans/axial_compact_fans_detail.php?pID=120054
http://www.ebmpapst.com/en/products/compact-fans/axial-compact-fans/axial_compact_fans_detail.php?pID=120092
http://www.ebmpapst.com/en/products/compact-fans/axial-compact-fans/axial_compact_fans_detail.php?pID=53731

There are spec charts to all of them.

Re: Extruder fan specification ?

💡 the papst ones have always been the rollce-royce in fans. reliable, long lasting and decently silent. they are not cheap but always worth the money... especially in an industrial environment, where reliability counts and fans are replaced following a strict maintenance schedule.

💡 update: 💡

➡ just measured the cooling capability of the fans at my printers:

A. genuine prusa i3 MK2 30x30 fan, forward direction (blowing into the extruder body):

0min 200°
1min 161°
2min 130°
3min 106°
4min 88°
5min 73°
6min 63°
7min 54°
7.42 stop

B. my own prusa i3 MK2S+ clone, 30x30 fan (chinese brand "MX", came with the cheap E3Dv6 clone) reverse direction* (-> sucking air out of the extruder body):

0min 200°
1min 162°
2min 129°
3min 105°
4min 86°
5min 72°
6min 61°
7min 52°
7.22 stop

now about the noise, measured in a distance of 20cm in front of the extruder:
A. 45dB(A) fan off -> 59 dB(A) fan on
B. 36dB(A) fan off -> 53 dB(A) fan on

as you can see by the idle noise, my 2nd printer (the clone) is located at a quiter place as my genuine kit. but at my second printer i also start a 40x40 fan to cool the electronics as soon as the hotend fan starts to spin... so it's noise has to be considered too.

*) for the cooling purpose of the coldend the airflow direction is irrelevant, i did this to avoid that heated air is blown at the p.i.n.d.a. .

Re: Extruder fan specification ?

Thanks for the figures from the original 30x30 fan.. prety close to my san-ace fan , 3-4 deg faster in the mid range and 30s overall faster to 50 but as previously discussed we're not really bothered by the cooling efficiency much below 150º and in fact my san ace 40mm fan was the fastest in the first minute.. not enough to be significant though. So I have a pretty silent fan and cooling as near as doesn't matter to original specs and the fan wasn't new but at €6 off ebay I bought a couple to have a spare and just soldered r/c jst male plugs on them and a femal onto the printer. Now fan changes are a simple unplug swap.

re the papst fans they don't list static pressure as such in the specs but if i'm reading the efficincy graphs correctly they are showing the pressure that will reduce the airflow to zero . most of them are in the 0.06 -0.08 inch range which is noctua territory ..ie not good.. the best two spin at 6000rpm and are more like 1.35 inch which is better . they are also listed as 26db .. the san ace I'm using have two extra blades, spin at 6300rpm, 26db, and offer 0.165 inch which is almost the same as the original 30x30 fan so I think i'll stop looking. at over $25-30 list price the san ace is top end too. Just lucky to find some cheap in Germany used. but not very looking at the state of the ones i received.

Re: Extruder fan specification ?

... Just lucky to find some cheap in Germany used. but not very looking at the state of the ones i received.
i wouldn't recommend to buy used fans, because they used to come from replacements due to maintenance plans, so it's quite likely that they are really worn out.

Re: Extruder fan specification ?

yeah but for testing purposes I wasn't paying £25 plus postage.. stripped bearings cleaned and relubed. no play or unusual sounds for now..

Re: Extruder fan specification ?

😳 sorry @jon.m: didn't realized that you've answered to jltx's funnel to provide "clean air" to the fan. thought you were refering to titus.o's post.

🙄 can't edit my previous post anymore, so i've to agree to your "phonograph" interpretation of jltx's funnel with this additional post !

@all: discard my posting above, based on a misinterpretation of jon.m's post 😕

I have not noticed that the fan is any louder, but the extruder fan is so loud, who knows. 😛