very weird Problem with ender 3s1- all usual solutions already tried.

[Mannitu78]

Hello folks, im coming over from a German Forum where i couldnt get any help or input, unfortunately. The problem is the weird unhealthy sound and the vibrations that come from my ender 3s1. Usually it starts after about 2 hours in longer prints, but sometimes it starts right away or after an hour. It apperas whenever the bed moves with a faster acceleration, often when it travels a distance thats longer than a few centimeters. I feel like the longer the print goes, the more severe it gets and it appears almost everytime the bed travels or changes direction. But its def. the longer and faster it travels, the more severe it is.

In the beginning of a print, for example if i print a raft for better adhesion, everything is smooth, because bed and extruder move in a slow way with only 50% speed, no fast change of direction or accerleration. The extruder wagon tends to have this problem as well, but not as often and not as severe. What does the problem look/sound like? Were talking about a vibrational, rumbling noise, you could think that the wheels are loose or that theres sand on the rails/profiles.

In severe cases you can also clearly see this on the surface of the print. I usually stop the print when it gets this worse, which has become really annoying. I had my printer for about 6 months before i started to register this mess. What have i done to fix it? Everything i could think of. I started with playing around with the wheel pressure, namely the exzenter screws, because they were my Nr.1 suspect obviously. Usually i had them tightened to a point where i could still turn the wheels without moving the bed, but i had to use quite some force.

I detached the belt to see how easy the bedwagon can be moved...all seemed well. I then tried to make the wheels so lose, i just turned the wrench a few millimeters over the point where the bed was still wobbling. You could turn all wheels with 1 finger now on spot with almost no force. I tried to turn them so tight that you basically could not turn the wheels anymore without moving the bed. The result was that you needed way more force to move the empty bed.

Much more work for the steppers now. However, none of it stopped the problem. I probably disassembled the printer at least a dozen times. Ive changed the belts, i have changed the wheels, i experimented with different belt tensions obviously, i put heatsinks and a little fan on my Y-axis-stepper, then i bought a new steppermotor without any result.

I have checked all wheels and the rails/profiles to see if there is any flat wheel or any markings/dents in the V-profil--nothing, its all fine. I put the printer on a couple of books left and right, so i could check the airflow/temps on the underside...seems cool to me. fans work, you cant feel any heat near the PSU or the intake fan thats right above the small board. No warm air building up there. Is it possible that the stepperdrivers overheat? IDK. But i doubt it. They have a heatsink and the small intake fan is right above them. If the undersite of the case is cool to touch, it would mean that they overheat even if a cool enviroment.

I also reduced all accelerations and jerks. Jerk is only 7mm/s now...Travel acc. i reduced from 2000 to 1200mm/s. i would say it made the sound a little less severe, but it didnt change the core problem. Regular accelerations from 500 to 400mm/s. Im printing with 50 or 60 mm/s. So yeah its making me a real headache for many weeks now. I just hope i find somebody who had the same symptoms and found the cause of this. Greetings,