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Strange noise when the X and Y axles move at the same time  

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kingof7eleven
(@kingof7eleven)
Eminent Member
Strange noise when the X and Y axles move at the same time

Hello,
I described my problem in the forum some time ago, but unfortunately nobody knew a solution. That's why I'm trying again.
My MK3S+ makes a lot of noise when the X and Y axles move at the same time and I also have grooves in the top layer.
Please have a look at the short video here (with sound) to see what I mean: http://bcd24.de/test/noise.mp4

I can say with certainty that it is NOT the print settings and NOT the model! I have 36 identical printers and only one has the problem.
The problem I have must be a mechanical problem.

Which I have already done:
-Changed and lubricated all bearings
-Realigned all axes-Checked and tightened all screws
-Checked the symmetry of the frame
-Replaced the complete hotend incl. nozzle'
-Cleaned the extruder
-Checked and re-tensioned all belts
-Cleaned all pulleys and checked for tight fit and correct distance to the motor
-Checked all screws on the heatbed

Nothing helped! 🙁
Is it possible that a motor on the X or Y axis is defective and makes these noises under load?
When I move the extruder or the heatbed by hand, no noise can be heard.

Thanks!
Sascha

Opublikowany : 07/04/2024 1:36 am
Eef
 Eef
(@eef)
Reputable Member
RE:

Hello Sacha, 
I did not have the same problem and not a shortcut solution. But maybe can help a bit analyzing what is going on. 
The motors go stepwise. Such a movement creates a "block wave". Because of the high frequency you hear is at high a bit rattling sound. 
When both motors X+Y (and also extrusion motor) run, these frequencies are combined giving even higher/mixed frequencies. 
This causes the machine to be "shaked" high frequency in all directions. (I did not have to explain this, because you must know all this already :-). It is just my "loud" thinking)
If there is play in joints, bearings, etcetera, this can cause quite some noise. You checked all bearings joints and did not find something special. So can be ignored. Maybe doublecheck, by pressing on several spots (when machine is running) against axis, motors, joints (anything that could have play in it). Pushing it in the "play" direction removes the play (while you hold it) and should give a different sound. 
-
Trouble inside one of the motors. If so the noise would be there, when only one motor is running, too. You don't mention that, so can be ignored.  
The movement may give resonance on other parts of the machine (or even around the machine). A part/plate/nut/screw/fastener of an enclosure, frame, what ever start sounding because of the movement. A frequency what hits the "own frequency" of that spot, will give the sound. This type of sound/rattle is not present at other frequencies. Hard to find if this is the cause. I would also try by pushing/pressing/holding all kinds of spots on the machine. Maybe changing printspeed (what changes the movements of the steppermotors a bit can help with the search). 

Just some ideas, hope it is of some help. regards, Eef

We will do what we have always done. We will find hope in the impossible.

Opublikowany : 07/04/2024 6:22 am
Dave
 Dave
(@dave)
Eminent Member
RE: Strange noise when the X and Y axles move at the same time

Hey Sascha,

I have the same problem with my machine as well.  I haven't been able to do the same level of diagnosis that you have, so I appreciate your findings.  I thought it was the bed bearings having issues, but now I'm not sure.  I look forward to any additional findings you come up with!

Dave

Opublikowany : 07/04/2024 1:57 pm
kingof7eleven
(@kingof7eleven)
Eminent Member
Topic starter answered:
RE:

 

Posted by: @eef

The movement may give resonance on other parts of the machine (or even around the machine). A part/plate/nut/screw/fastener of an enclosure, frame, what ever start sounding because of the movement. A frequency what hits the "own frequency" of that spot, will give the sound. This type of sound/rattle is not present at other frequencies.

Normally, I would also first suspect a resonance problem after I was able to rule out defective bearings on the X or Y axle.
However, I also have diagonal grooves in the surface of the printed parts (only on the top, not on the sides!), which must have something to do with the problem.
Attached is a picture where you can see a part (housing cover) from the problematic printer on the left and the same part printed on another MK3S+ on the right. Same gcode.

This post was modified 8 months temu by kingof7eleven
Opublikowany : 07/04/2024 11:12 pm
Eef
 Eef
(@eef)
Reputable Member
RE:

That narrows down quit a lot. 
- would be nice to know if you have same issue when there is only one direction X or Y? 
- and also interesting if you have the same when the printing direction is the other diagonal so not from upper left to downright, but upperright to downleft
Some ideas: 
- Imagine something is not correctly fixed between extruder carriage and X-axis (bearing probably not, but fasteners, broken backplate?) And there is a slight "play" there (hard to notice manually, because of the flexibility of the X-axis, what moves too when pushing/pulling the carriage). Depending on direction this could cause a slight "pulling" the nozzle up in one direction and "pushing" down in other direction, causing the groove. 
- Imagine the bed can tilt/stagger a tiny bit. This could maybe give a simular effect. I don't think this is the cause, because then the grooves would be more irregular of different on different places on the bed. 
- Imagine an issue with the belts. (But can not imagine how this would cause a groove. For the groove there has to be something with heigth of nozzle. )
Probably nothing with extruder itself giving more/less filament, because you would see then irregular printing and not a "nice" groove. 

So I would check the mounting of the extruder on the axis. 

 

We will do what we have always done. We will find hope in the impossible.

Opublikowany : 08/04/2024 5:43 am
kingof7eleven
(@kingof7eleven)
Eminent Member
Topic starter answered:
RE: Strange noise when the X and Y axles move at the same time

Yesterday I dismantled and checked the Exdruder for the 4th time. Couldn't find a problem there. The grooves only appear diagonally but in both directions.
I also removed the filament, increased the Z distance and started a print without filament and without the nozzle touching the bed.
The strong noises in the diagonal movement were still there. The axes of the print bed are fixed and straight. I have already changed the bearings and the brackets are also tight.
I now think it is due to one of the motors (X or Y).
You can actually notice bearing damage on the motor when you turn the motor by hand and it clicks.
This is not the case, but perhaps it behaves differently under load.

Opublikowany : 10/04/2024 4:34 am
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