MK4 Factory Assembled - Bad Bearings?  

RE: MK4 Factory Assembled - Bad Bearings?

Somebody couple days ago had the same problem and they got replacement bearing if you can I recommend in about 2 hours it will be less wait time

RE: MK4 Factory Assembled - Bad Bearings?

Chat time aren't to bad now also turn volume up and you will get alerted while you do something else 

RE: MK4 Factory Assembled - Bad Bearings?

Yeah, it's down to 17 minutes.  Thanks.

RE: MK4 Factory Assembled - Bad Bearings?

Please let us know how it goes 

RE: MK4 Factory Assembled - Bad Bearings?

Support claims it's a loose screw somewhere, which is BS.  I checked every screw and bolt on the thing and no issues.  Here is a much better video of the sound...

IMG_2080

RE:

Almost sounds like something rubbing on the fan?

Open the fan door and make sure all the wires are tucked in securely…..

EDIT - just realised it can’t be that since the fan in enclosed on that side anyways…… just sounds like a vibration from something loose….

RE: MK4 Factory Assembled - Bad Bearings?

Going to re-check everything under the bend when the current print ends later.

RE: MK4 Factory Assembled - Bad Bearings?

check out these two quick access hotend mounting screws

RE: MK4 Factory Assembled - Bad Bearings?

Saw a video on YouTube where someone had a noise - he tightened both Hotend thumb screws and the noise went away…..

RE: MK4 Factory Assembled - Bad Bearings?

Found a M3 bolt that was missing on the Y axis but fixing that didn't do anything.  I've checked every single joint, contact point, screw, etc and the noise persists.  As you can see/hear it's only on the left side of the bed.

https://youtube.com/shorts/dtYscg-frOo

RE: MK4 Factory Assembled - Bad Bearings?

I’m not sure what to suggest but am awfully intrigued as to what this could be!! Hopefully someone more knowledgeable then me will chime in with some suggestions!

RE: MK4 Factory Assembled - Bad Bearings?

is there the same sound if you turn off the fans?

RE: MK4 Factory Assembled - Bad Bearings?

Yeah, fans aren't the culprit.

I just got done degreasing and packing the y-axis bed bearings and no change in noise - still loud as ever in the same motions.

RE: MK4 Factory Assembled - Bad Bearings?

I'm now questioning the X axis as the only remaining culprit.

RE: MK4 Factory Assembled - Bad Bearings?

Update 5: In contact with support and this is their current response as I'm not the only one experiencing the issue...

our developers are currently looking into what can be causing these issues. While the final solution is still in the works, I can recommend following steps to mitigate the issue:

• check the belt tension
• increase printing speed by ~20%
• try changing tension on these screws holding the X bearings some more, there is a high likelihood of finding a sweet spot where vibrations are minimal

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Posted by: @jeremy-3

our developers are currently looking into what can be causing these issues. While the final solution is still in the works, I can recommend following steps to mitigate the issue:

• check the belt tension
• increase printing speed by ~20%
• try changing tension on these screws holding the X bearings some more, there is a high likelihood of finding a sweet spot where vibrations are minimal

I hope there's a better solution than that before they build/ship my MK4!  That noise is unacceptable, and playing about with speed, belt tension, and screw torque in pursuit of "...finding a sweet spot..." is not what I signed up for when buying a factory-assembled, factory-tested printer. 

It does not seem that all MK4 units have this issue (or maybe they do, and others just haven't hit the right speeds/movements that exhibit it).  In any case, Prusa is pretty good at finding solutions and providing fix procedures -- so I sure hope they will come up with a standard solution for this soon.

RE: MK4 Factory Assembled - Bad Bearings?

You can see in the attached that when you remove the small bottom plate, there is nothing retaining the bearings.  I can slide those bottom bearings out of the toolhead and do a X movement right or left and still get the noise.  So it's either the top third bearing (can't tighten/loosen it per say) or something with the housing itself.

RE: MK4 Factory Assembled - Bad Bearings?

Update 7: Support has confirmed this to be a design flaw, of which they do not currently have a solution or a fix or an ETA. They do not know if using the machine as-is would do harm to the Nextruder or other toolhead components. The noise has gotten louder and there are noticeable artifacts on the prints.

This after completely tearing down and rebuilding the toolhead, reseating the bearings, trying pads under the bearings, etc.  It isn't the bearings themselves that are bad, unfortunately.

RE: MK4 Factory Assembled - Bad Bearings?

Mine did this the first print out of the box. I traced the noise to the power supply and on inspection, it was the toroidal inductor (there's only one in the one I have) making the noise due to vibrations caused by very specific stepper motor speeds. I stuck a small piece of silicone tubing between it and the transformer next to it and that has prevented that vibration and stopped the noise.

Standard disclaimer - I don't recommend anyone take apart their power supply.