I have a noise on my X1C that is really getting me down. It is so unbearable that I am currently only printing with the A1. I’ve already turned the printer over and in my opinion the noise is either coming from the lower bearing of one of the Z axles or, more likely, from the belts that run over the pulleys/bearings.
In any case, I had localized it down there with my smartphone and an app for measuring volume. In other forums I had read something about lubricating the backs of the belts, I had also done this minimally and it had worked immediately, but now it is even louder and to be honest I am unsure whether it is so good to grease the belts.
It’s definitely not the Z spindles themselves which are well lubricated. The bearings also look well lubricated from the inside.
I made a video of the noise…
Bambu Lab X1 Carbon - Squeaky noise when moving the Z axis (youtube.com)
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Hard to judge what it can be based on the sound recorded by your phone. Definitely not right, though. I don’t think it’s belt noise, though if it is, removing the belt and turning the idlers by hand should expose the bearing that’s rough.
Three possibilities I can think of… there’s a scrap of filament jammed in to one of the Z stage screws, there’s an alignment issue with the build plate or with the position of the plastic bezels at the back of the printer resulting in interference when the Z stage moves (the back is the only place the build plate is close enough to anything for this to be a possibility but it’s a long shot), or lastly that you have a seized bearing or bad ball screw on one of the Z stage rails or screws or belt pulleys.
I think if it was a belt/pulley the sound wouldn’t change depending on where you are on the Z axis. It’d happen at the top same as it does lower down. The belt goes around many times for each CM of travel. Same logic applies to the bearings the Z axis components ride on. If it’s only happening down low, I think it’s likely a ball/screw issue.
You’re going to have to take stuff apart to figure it out I’m afraid.
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I am having the same issue and it really sucks that I have to perform a teardown and try to resolve this on such a new printer.
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I have hit the same issue. printer is 6month old, and that sound is pretty loud… Trying to share a link of the video but can’t seem to include link.
I guess it is time to open the bottom? not looking forward to this…
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I have watched the video and have the exact same!!! Grrr!
30-40mins later, sorted i places a drop of machine oil on a pully underneath the X1C 
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I think I’m going to have to do the same thing. I mainly hear the noise when the bed is near the top and is z hopping. It started a few weeks ago.
The noise sounds like it is coming from under the printer.
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Correct. It’s not covered so easy to do. Just one drop of oil on the metal pulley and it’s gone. It is caused by the belt rubbing against the pulley
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How do I access the pulley?
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Lift up the printer or turn it on its side and you’ll see all the puillys.
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You mentioned the belt rubbing, so are you putting the oil on the outside part of the pulley the belt touches or just on axle of the pulley?
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I did put a large drop on the pulley with the intention of just lubricating the bearings but it went on the belt too. But it did stop the squeaking almost immediately
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I reached out the Bambu to confirm what to do and this was their response:
Judging from your video, the noise could be from the friction of the Z belt and wheels. The four areas highlighted in red circles in the diagram are potential sources of friction.
We recommend applying lubricating grease at the Z belt tensioner idler wheel to address this issue and make the noise.
If the noise persists after lubrication, please refer to the wiki: Replacing the Z timing belt | Bambu Lab Wiki
You can follow steps 5 and 6 in this wiki article to remove and inspect the tensioning idler assembly of the Z belt for any misalignment shown in the picture below.
EDIT: They also sent a video to show where to put the grease
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I can confirm that putting the grease on the idler pulley as shown in Bambu’s video eliminated the z hop sounds I was getting for the first few layers.
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Thanks for the detailed explanation. I got rid of the noise by lubricating the back (flat side) of the belts. Looking at your video, it seems to be greasing the same areas. However, I used a lot less as I was worried that a lot of dirt would collect on it. Grease magically attracts dust.
I signed up here just to say that I had exactly same sound and couldn’t identify what was wrong. And lubricating that pulley on the bottom solved it! Ugh, what a relief not to hear this sound anymore
hey i’m having the same problem. I see that you used grease to fix the issue would you mind telling me which parts and which grease did you use ?
tnx
Having the very same issue now, with x1c with a bit over 1000 hours of printing. Will apply the grease and ordered a few spare z-belts too…
