Resonance / Vibration in X-axis carriage/extruder assembly during Z-movement
 
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Resonance / Vibration in X-axis carriage/extruder assembly during Z-movement  

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F0erster
(@f0erster)
Eminent Member
Resonance / Vibration in X-axis carriage/extruder assembly during Z-movement

Hi,

i just built my new MK3S+ kit (according to manual - and now dissassembled and re-lubed the Misumi bearings of all axes) and the printer so far runs well. Only a few failed prints that i attribute to my inexperience with temp and speed settings but otherwise very good print quality. 

The thing that annoys me a though is a loud rattle/vibrating noise during Z axis travel movements. I tried to locate the noise and read many posts about the display unit and the Y-carriage making the noise and i can exclude them. I also installed silicone gaskets on all steppers and retightened and adjusted tension of the bearing holders of the Y-carriage. I tried to squeeze or hold the PSU/Einsy housing and the Z-rods during the movement to try to dampen the noise with to no avail. That leaves the X-carriage/extruder as the culprit so far. Holding my ear to it, it seems to originate from there, too. The printer stands on its rubber feet on a large bathroom tile, which lays on a rubber mat which i laid on foam.

I will post a video shortly to hopefully capture the sound. I was, in my opinion, quite diligent while building the extruder unit so i want to exclude loose screws or some kind of misassembly, but of course it may be possible i did something wrong.

Maybe one of you experienced this before and can help me narrow this down.  Thanks 🙂

 

 

Posted : 05/08/2021 1:46 pm
Dan Rogers
(@dan-rogers)
Noble Member
Squash ball feet and be done with it.

The loud buzz can have many sources.  Anything a little loose that rattles - like the balls in those stock linear bearings.  I just built a MK3s+ two weeks ago and outfitted X and Y with drylins from birth.  No rattles.  Whisper quiet.  Added squash ball feet and now I can really only hear fast movements as a whisper of motor noise.  A full Z elevation will still make some rattles - it doesn't hurt or change print quality at all (Z does not move much at all during a print).  Go for the win (quiet printer) - best thing you can do is squash ball feet.  Layers and layers of mats and rubber don't suppress vibration from passing to the table you are sitting your printer on.  The larger surface areas just transmit the noise better.

Posted : 05/08/2021 2:37 pm
F0erster
(@f0erster)
Eminent Member
Topic starter answered:
RE: i dont think the problem are vibrations that transfer into my base

 

Hope you can see the video, for some reason it does not show for me. Only the sound gets played for me.

Calibration Noise

This is how the 3x3 calibration before a print sounds like. Linear X-Y Movement is alright, smooth, fast and nothing out of the ordinary to my ears. The Z-Noise however is a clear sign of something rattling/resonating inside the printer itself. I found one culprit already which was the X-Belt pulley on the right. The pulley of course has clearance to the sidewalls of the orange housing and in particular Z-sectors during continuous Z-movement, gets excited by the movement and makes rattling/vibration noises. I was able to prevent them by pushing the belt to the side and getting the pulley to bind to the housing. Not sure how to deal with that yet, as free movement of the pulley is essential, but clearance results in the pulley being able to vibrate.

The other noise comes, as specified, from the extruder and the pitch or hum can be changed by pressing against it a bit. I am not sure if its the bearings or something inside that gets excited. I also am not sure if i should look at the extruder resonating, or the Z-Axis exciting everything as the problem. Maybe you are familiar with that sound.

 

Posted : 08/08/2021 12:41 pm
PoorNeko
(@poorneko)
New Member
Same problem

Hello!

By description, sounds exactly like my problem. Have you solved it?

Posted : 21/09/2021 8:45 pm
Dan Rogers
(@dan-rogers)
Noble Member
About two months back I built another MK3S+

During assembly I made the following changes = all geared at noise and print accuracy.

X and Y carriage LMU8 bearings - I put them all in the spares bag and left them there.  Bought a pack of Drylins, which is enough to do the X and Y carriage on an MK3S.  For Z, I greased the living grease-fitting out of the bearings that ride the Z rod in the X carriage.  Those suckers rattle - every little ball in there rattles.  Unless you squeeze them, but that's a total art.

Y motor mount - that sucker allows the motor to rattle against the back frame in certain vibration scenarios.  I put a piece of mylar between the motor mount and the back frame and screwed it down. This increases the distance enough to prevent the motor from rattling on the frame, and doesn't increase it enough to need to mess with belt length.  There is a better motor mount that also solves the pulley not being centerable that you can get on the prints library that also increases the motor spacing from the back chassis.

Check that the dust catchers are not too far down on the Z shafts.  Those can rattle.

X belt tension needs to be in the sweet spot.  Y belt tension needs to be in the sweet spot.  (on the physical tension gauge - print library) Or the whole shebang can rattle or buzz.

Squash ball feet (snap-ons from the print library) - mandatory to quite table caused resonance.  The tiny little noises can be magnified like a violin body on a normal table top.  Want to see how much?  Pick up your printer (carefully) by the metal at the top during a buzzy print.  Any noise that disappears or gets quieter is from the table, not the printer.

Vigilantly assemble and re-assemble the front panel assembly.  Put a piece of tape over the buzzer on the inside of the front cover (damn thing is dangerously loud otherwise) and use vinyl or electrical tape between the plastic parts - dampens the occasional resonance buzz.

I think that's it.  Holy smokes the new printer is quiet.  Not as quiet as my old one (the moons motor upgrade cuts 30db from the printer), but those suckers aren't cheap to get shipped from china.  No buzzes.  No annoying Z buzz (the elimination of 70% of the bearing balls did that all by itself), no Y motor buzz.  No front cover buzz and no bleeding ears from the buzzer volume.

 

Posted : 22/09/2021 6:38 am
PoorNeko
(@poorneko)
New Member
RE: Thanks for answer

Thanks for answer.

Fortunately,  I have only problems with X axis, but it is quite an anomaly, because I cannot figure out what rattles. The only thing I can see is that my belt vibrates quite a lot (you can see that on attached video) and I suspect vibrations are transferred to the rods and then to the bearings. 

Video link (mail.ru) - media attachment does not work

If I remove belt and move extruder by hand, it is all good. 

Belt tension only shifts that "resonance" speed-wise, so it occurs at different speed.

I talked about that with Prusa Support, but this thing is quite hard to figure out when you do not have printer on hand, so I do not blame them.

Have you ever had this belt behavior when dealing with noise issues?

This post was modified 4 days ago 2 times by PoorNeko
Posted : 22/09/2021 8:12 am
F0erster
(@f0erster)
Eminent Member
Topic starter answered:
RE: still rattling

@PoorNeko

nope, not resolved the X Axis rattling yet. I may need to disassemble the whole carriage to get to the noise source probably.

@Dan Rogers

great writeup! I do not use drylins but i excessively lubed up all the LMU bearings on all axis as i was observing Y axis and Z axis noises too. But no luck, printer is definitely really quiet during normal printing now, but any faster Z axis movement still excites the X carriage to ridicoulus levels of rattling.

I believe to have built the printer diligently, tightening everything accordingly an all, but something must be (too) loose inside the carriage. Here one example video of the noise during Z travel:

Video

It's definitely not the fans, as i tested by holding them during travel already. From the outside, everything is tightened down snugly. Also, it's not the Z-Bearings as putting them under some load by pushing/pulling changes nothing. The noise also notably comes from the X-carriage only.

This post was modified 4 days ago by F0erster
Posted : 22/09/2021 8:29 am
Dan Rogers
(@dan-rogers)
Noble Member
Your X axis carriage is holding 5 sets of bearing balls.

If you are using linear bearings with bearing balls, they rattle on Z movement.  There really is nothing you can do about the balls rattling.  Grease can reduce it a bit, but it will come back as the grease sublimates or whatever grease does that needs more grease.  The geared idler on the extruder will probably rattle around a bit as well.  The idler pulley on the end of the belt can rattle - cut a felt washer and that one goes away. 

  

Posted : 22/09/2021 12:43 pm
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