Quieter Fans

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willnewton
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Re: Quieter Fans

Post by willnewton » Sat Feb 06, 2016 2:31 pm

I was thinking that due to the relatively low power needed to operate the fan, it might work. Ah well, but now I know.

Thanks Jin!
I'm finally back to where I started two days ago!

A thread with some stuff in it I update every once in a while. viewtopic.php?f=8&t=9
See some of my stuff http://www.thingiverse.com/willnewton/about

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ednisley
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Re: Quieter Fans

Post by ednisley » Sat Feb 06, 2016 3:14 pm

willnewton wrote:the relatively low power needed to operate the fan
The "relatively low" must be in relation to the resistors.

A string of 10 + 10 kΩ resistors will draw 1.2 mA from a 24 V supply: (24 V) / (20 kΩ).

The first small 12 V fan I found in the heap draws 120 mA, 100 times the current in the resistors.

To make the fan current "relatively small", you'd want the ratio to go the other way, but a resistor string drawing 12 A from the supply to get the right voltage for a 120 mA fan wouldn't work the way you want... [grin]

Which is why those cheap buck and boost supplies from eBay make so much sense. You get exactly the right voltage for the fan (or LEDs or whatever) with good regulation, minus all the aggravation, from whatever power supply you have.

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willnewton
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Re: Quieter Fans

Post by willnewton » Wed Feb 24, 2016 11:36 pm

Well, I have modded my extruder head fans, power supply fan, and added dampers to my X and Y motors.

Holy crap! I keep forgetting this thing is on. It is super quiet.

Power supply mod for Noctua 60mm fan. This is the first mod you should install, just change a connector and swap it. It is a huge reduction in noise vs. the stock fan. You don't have to mod the case like I did, but it helps keep the air flowing through.
m2psfan1.jpg
Cut out the fan guard. This is a huge restriction point. The fan stays covered by the MG case.
m2psfan2.jpg
Clean up your cut so no mess gets in the power supply.
m2psfan3.jpg
Change the connector to the one from the old fan.
m2psfan3.jpg (97.05 KiB) Viewed 3609 times
m2psfan4.jpg
Remove the MG end cap cover for improved ventilation
Last edited by willnewton on Thu Feb 25, 2016 1:00 am, edited 3 times in total.
I'm finally back to where I started two days ago!

A thread with some stuff in it I update every once in a while. viewtopic.php?f=8&t=9
See some of my stuff http://www.thingiverse.com/willnewton/about

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willnewton
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Re: Quieter Fans

Post by willnewton » Wed Feb 24, 2016 11:39 pm

Here is the new fan mount and duct. STL file available on Thingiverse. As suggested, I used a 24v to 12v buck converter I purchased for R/C use to run the 40mm bed fan.

http://www.thingiverse.com/thing:1368032
m2fans.jpg
Dual 40mm
And the dampers!
m2dampers.jpg
I'm finally back to where I started two days ago!

A thread with some stuff in it I update every once in a while. viewtopic.php?f=8&t=9
See some of my stuff http://www.thingiverse.com/willnewton/about

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zemlin
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Re: Quieter Fans

Post by zemlin » Fri Feb 26, 2016 2:50 pm

My fan mods - I've had my M2 for just under a month. My approach to quieting the fans was to replace them with larger fans that run slower. Both the bed fan and the electronics fans were replaced with 80mmx15mm thick 24V fans. I just bought cheapo fans on eBay.

I made a duct/mount for the bed fan to bring the air flow down to 40mm wide. I put a honeycomb flow straightener which made a big difference in keeping the flow directed at the nozzle area rather than blowing off to the side. I have also learned over the years that having a fan grill too close to the fan blades is a source of noise, so my grills are offset from the fan blades by 1.5mm-2mm, depending on the fan size. I did not slow this fan, since it is adjustable already in the software. I did, however, put a .47 uf capacitor in series with the fan to quiet PWM ring. The duct is mostly a .75mm thin wall to keep the weight down. Initially I made a shallower duct that kept the fan much closer to the rail, but the steep angles in the transition caused airflow problems.
IMG_1880.JPG
IMG_1886.JPG
For the electronics enclosure, I took a rather round-about approach, but since my machine is still under warranty I did not want to cut metal just yet. I printed a plenum that hangs off the side of the enclosure. Mounting the fan right under the Y-table on the printer would have really restricted the area available for air flow, so I moved it out to the front of the machine where I could put more space under the fan. Once warranty runs out I will probably relocate this fan into the enclosure - if there is room. To slow this fan it has a 120 ohm 5W resistor in series with it. Moves a lot more air than the little squirt that was in the box, but is almost silent. The resistor is mounted inside the plenum so it doesn't add any heat to the electronics enclosure and gets good airflow to keep it cool. 5W is much larger than it needs to be - but the resistors were cheap.
IMG_1882.JPG
I also put a 12V 80mm fan on the power supply - this is just stuck on top of the internal enclosure with a simple adapter I printed out - I used two of the 120 ohm resistors in parallel to slow this fan. I will relocate this one for sure once I can cut metal on this machine.

dramsey
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Re: Quieter Fans

Post by dramsey » Mon Mar 07, 2016 10:23 pm

Does the electronics box even need a fan? There's nothing with a heat sink that I can see, and the tangle of cables means airflow is going to suck anyway.

(I ask 'cause the lone 40mm "quiet" fan I had laying around actually sounds like a little banshee, and I thought I'd check before ordering the Noctuas...)

jsc
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Re: Quieter Fans

Post by jsc » Tue Mar 08, 2016 1:04 am

I do recall dimly a post from MG (Rick?) that the electronics box fan was mostly superfluous. I'd guess it serves mainly to split the 24V. Presumably two 12V fans are cheaper or easier to source than one 24V fan?

dramsey
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Re: Quieter Fans

Post by dramsey » Tue Mar 08, 2016 1:08 am

Hm. If it's to "split the 24V", does that mean running without the fan-- I.e. simply unplugging it-- would be a Bad Thing?

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sthone
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Re: Quieter Fans

Post by sthone » Tue Mar 08, 2016 1:38 am

dramsey wrote:Hm. If it's to "split the 24V", does that mean running without the fan-- I.e. simply unplugging it-- would be a Bad Thing?
It splits the 24 volts between the two 12 volt fans (Extruder and the Electronics box fans). If you unplug it you lose the extruder fan too (not recommended if you run a V3B extruder you can only do that with the V4.) I've been running for quite awhile without the extruder fan but I did put a 24volt fan in the electronics box. I think insta has been testing running without either but you'll have to see if he chimes in on that to see how it's been going.

As for quite fans though.... Someone posted a link to these blower fans on Amazon before and I've been using them as bed fans and they are super silent. I was going to rig one up as a electronics box fan too I just haven't gotten around to it yet.
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dramsey
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Re: Quieter Fans

Post by dramsey » Tue Mar 08, 2016 2:17 am

Well, I ordered a couple of the Noctuas anyway, so I shall live with Shrieky until then...
Last edited by dramsey on Thu Mar 10, 2016 3:47 am, edited 1 time in total.

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