Print fan makes a buzzing noise at around 50% speed or below
 
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Trimetric
(@trimetric)
Trusted Member
Print fan makes a buzzing noise at around 50% speed or below

I've been using my MK3S+ for about 2 weeks and it's working fine. I've noticed since the beginning this buzzing sound and I thought at first it was the stepper motors (I've never owned a 3d printer before). Turns out it's the part fan and it only happens when it's running about 50% speed or lower. Seems to max out at around 30% speed. I've tried tightening and loosening the screws and holding the fan while it's running but it doesn't seem to make a difference. I also checked to make sure the wires or nothing seem to be hitting the fan blades but the shroud on this fan makes it hard to troubleshoot too much.

The pitch of the buzzing changes if I change the speed and goes away completely at around 55-60%.

Is this normal or do I have a bad fan? I did confirm the fan is putting out air at the speeds it is making the buzzing sound.

Posted : 20/03/2021 6:59 pm
Clarmrrsn
(@clarmrrsn)
Honorable Member
RE: Print fan makes a buzzing noise at around 50% speed or below

If there are no filament hairs etc in the fan then probably just a bad fan motor, some get bits of crud dragged into the fan, that can generate noise, clean it out and if that does not work speak to prusa live chat, sure they will assist.

This post was modified 3 years ago by Clarmrrsn

Tank you very much!

Posted : 20/03/2021 7:34 pm
Trimetric liked
Dan Rogers
(@dan-rogers)
Noble Member
RE: Print fan makes a buzzing noise at around 50% speed or below

Also, check your fan shroud for cracks.  If you have installed any fan redirection parts, check that they are not what is buzzing instead.

Posted : 22/03/2021 5:11 pm
Trimetric
(@trimetric)
Trusted Member
Topic starter answered:
RE: Print fan makes a buzzing noise at around 50% speed or below

It still makes the sound even when it is detached from the extruder and shroud so I'm pretty sure it's coming from the fan itself. I reached out to support and they said "this is fan is known to be much louder than the Noctua". I gave them a link to a video with the noise thinking he might offer to replace it, but he suggested I try a few drops of oil first.

I'm not exactly sure how to oil it, if I remove the sticker on the top side, will that expose anything? I don't really want to separate the fan casing unless I had a replacement handy.

Posted : 22/03/2021 5:15 pm
Clarmrrsn
(@clarmrrsn)
Honorable Member
RE: Print fan makes a buzzing noise at around 50% speed or below

@trimetric

You wont damage it if you are careful.

http://www.dansdata.com/fanmaint.htm

This might help, there is a sleeve bearing inside , under the label  if you carefully pull it back without getting fingerprints on it you should be able to stick it back down, pop 1 or 2 drops of light oil into the bearing, not sure exactly what these look like but the link above will give you an idea of what to do, dont use too much oil, you dont want it going everywhere.

You dont need to strip the fan.  Should be wble to peel the label back and oil it.

TBH if the fan is noisy will most probably need replacing at some point.

This post was modified 3 years ago by Clarmrrsn

Tank you very much!

Posted : 22/03/2021 5:56 pm
Trimetric
(@trimetric)
Trusted Member
Topic starter answered:
RE: Print fan makes a buzzing noise at around 50% speed or below

@clarmrrsn

Perfect, I'll give that a shot. Honestly, given the sound of it I thought Prusa might replace it under warranty (although looking they are only about 8 USD if I bought a new one). Perhaps they still would if the oil doesn't help it.

Attached is the video I showed them, I was just playing with the speed in the OctoPrint slider to find the most noise (about 35% or so in this video)

Attachment removed
Posted : 22/03/2021 6:11 pm
Clarmrrsn
(@clarmrrsn)
Honorable Member
RE: Print fan makes a buzzing noise at around 50% speed or below

Cant get that video to play, keeps crashing.

 

Tank you very much!

Posted : 22/03/2021 6:48 pm
Trimetric
(@trimetric)
Trusted Member
Topic starter answered:
RE: Print fan makes a buzzing noise at around 50% speed or below

@clarmrrsn

Weird. It won’t play directly from the link but if you download it plays fine. I tried to attach a YouTube link but the forum denied me. Not sure how you are supposed to share videos. 

Posted : 22/03/2021 7:39 pm
Clarmrrsn
(@clarmrrsn)
Honorable Member
RE: Print fan makes a buzzing noise at around 50% speed or below

@trimetric

I normally just paste the you tube link jnto the post.

Tank you very much!

Posted : 22/03/2021 9:29 pm
Trimetric
(@trimetric)
Trusted Member
Topic starter answered:
RE: Print fan makes a buzzing noise at around 50% speed or below

I tried using the little Insert/Edit Media icon. Maybe that was too fancy 😀 

Posted : 22/03/2021 9:42 pm
Clarmrrsn
(@clarmrrsn)
Honorable Member
RE: Print fan makes a buzzing noise at around 50% speed or below

Yip, that sounds buggered.

Are you sure the impeller is not split? Rotate it round and inspect it very carefully, tbey can get a crack in them and make that sort of noise, might be hard to see.

You are looking at the blades that are inside the casing, if you look carefully might be able to see, my MKs is running so I cant check.

Could be the bearing, always hard to tell in a video.

This post was modified 3 years ago by Clarmrrsn

Tank you very much!

Posted : 22/03/2021 9:48 pm
Trimetric
(@trimetric)
Trusted Member
Topic starter answered:
RE: Print fan makes a buzzing noise at around 50% speed or below

@clarmrrsn

I took a good look at the blades and don't see any damage. The fan feels like it rotates freely. I removed the sticker and put a drop of 3 in 1 oil in there but it didn't help. I'm saying it's the bearing at this point and going to see if Prusa will send me a new fan under warranty (the printer is only about a month old).

Thanks for the help.

Posted : 23/03/2021 1:14 pm
Tree Runner
(@tree-runner)
New Member
RE: Print fan makes a buzzing noise at around 50% speed or below

I've had my kit printer running for several days now. My print fan makes a rattling noise while the extruder is printing. The fan blades are not touching anything it's not the fan blades. When I change speeds while the printer is warming up in the tune menu the fan runs perfectly quietly it all speeds. It's only when the extruder is actually printing that the fan rattles. I'm noticing some looseness in the axis of the fan blade axle. You can move it up and down slightly and I'm thinking that's the origin of the rattle. It's quite annoying and I'm wondering if anyone else has experienced this issue.

Posted : 28/03/2021 6:48 pm
Trimetric
(@trimetric)
Trusted Member
Topic starter answered:
RE: Print fan makes a buzzing noise at around 50% speed or below

@tree-runner

Same for me. The fan can be pushed in some amount. It turns nice and smoothly but anything below about 50% it makes a rattle or buzzing sound. 

Posted : 28/03/2021 9:03 pm
Tree Runner
(@tree-runner)
New Member
RE: Print fan makes a buzzing noise at around 50% speed or below

You are right, the noise is mostly when it's running slower. I think we may have both received fans from a batch that are a bit defective. I'm super happy with this printer because with the exception of this fan it is so much quieter than the one it replaced and turns out amazingly nice prints. I think the slight vibration of the extruder body causs the fan to rattle. I don't think this will cause the fan to fail. Maybe we could get a replacement from Prusa, but I don't relish the thought of replacing the wire in The wire bundle or splicing the wires.

Posted : 28/03/2021 11:33 pm
Trimetric
(@trimetric)
Trusted Member
Topic starter answered:
RE: Print fan makes a buzzing noise at around 50% speed or below

@tree-runner

Yeah. This noise is literally the loudest thing on the printer which is pretty amazing really. I’m going to see if Prusa will send another fan and hold onto it until I have some other maintenance to swap it out. Luckily it’s only an 8 USD part so not a big deal to buy. 

Posted : 29/03/2021 1:05 pm
Clarmrrsn
(@clarmrrsn)
Honorable Member
RE: Print fan makes a buzzing noise at around 50% speed or below

@tree-runner

Try a few drops of machine oil or similar into the sleeve bearing, peel the label back carefully, try and avoid using your fingers so will stick back down, put a few drops in, not too much and watch does not drop on the bed.

Wonder if there is a bad batch of fans going around.

Always worth asking Prusa Chat, if you have oiled it first will savs a bit of time as they will probably ask you to do it first.

Tank you very much!

Posted : 29/03/2021 1:26 pm
Tree Runner
(@tree-runner)
New Member
RE: Print fan makes a buzzing noise at around 50% speed or below

Thanks for the input, but lubrication is not the issue. I just corrected the problem here and quieted the fan. I took the fan housing apart and using a whole bunch of tools including channel lock pliers, a magnet, rubber bands and various hardware, managed to push the axle into the fan blade assembly a little further. I don't recommend attempting this unless you have a spare fan handy. There was just too much axial slop allowing the fan blades to jump up and down and rattle.

 

Posted : 29/03/2021 3:38 pm
Clarmrrsn
(@clarmrrsn)
Honorable Member
RE: Print fan makes a buzzing noise at around 50% speed or below

@tree-runner

Good to know.

TBH I have never really stripped one of these fan types down, normally when they start to go noisy they get replaced, its not worth the labour to repair a fan.

Would be good if you could feed this back to Prusa as clearly there is a manufacturing issue at fault here that they probably need to address.

Thats 2 in the space of a week have reported this.

Tank you very much!

Posted : 29/03/2021 3:48 pm
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