Z motor noise due to loss of X-axis leveling
My MK3 has severe Z motor noise.
I found out that it is caused by the loss of X-axis leveling. i.e. the X-axis is not parallel to the print bed surface.
The left side (homing side) is always lower then the right.
The situation improved a lot after turning the threaded rod on the left side to level the X axis manually.
BUT, the left side will drop again after sometime and I needed to do the manually leveling all over again.
What's wrong? Mechanical? Electronics? Firmware? Any idea?
Re: Z motor noise due to loss of X-axis leveling
mechanical. both motors go to the same driver output. do calibrate Z to level them out 100% or close. check bearings, lead screw nuts and lubricate? general maintenance. check motor caps too, make sure the're not too tight.
Re: Z motor noise due to loss of X-axis leveling
I think I have the same issue. I own my mk3 for 3 weeks and never had any problem with the first layer calibration. now the right side of the printing bed is definitely higher than the left side. when this issue appeared the Z-axis started to produce a loud noise. so, what's the solution? I've already tried to tighten everything up and to my eye, it's all sturdy
Re: Z motor noise due to loss of X-axis leveling
loosing the lead screw bolts reduced the noise quite a bit
The Latest Firmware can be found here https://github.com/prusa3d/Prusa-Firmware/releases
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Re: Z motor noise due to loss of X-axis leveling
I think I have the same issue. I own my mk3 for 3 weeks and never had any problem with the first layer calibration. now the right side of the printing bed is definitely higher than the left side. when this issue appeared the Z-axis started to produce a loud noise. so, what's the solution? I've already tried to tighten everything up and to my eye, it's all sturdy
You might want to check the front zip ties holding the bed to the rails.
The front zip ties are prone to get loose because the magnets are so strong that every time you lift up and remove the metal sheet when printing finished, there is a uplifting force to the bed. That was my issue, might be yours too.
Re: Z motor noise due to loss of X-axis leveling
not in my case. I tried to lose a bit all the screws holding the motors (i mean, not overtighten) and the Z-axis noise is gone. but I still get an awful result when I launch the First layer calibration.
I also used a level to see if there was a misalignment between the plate and the X-axis and to my eye they are perfectly aligned.
Re: Z motor noise due to loss of X-axis leveling
this is the resoult 
Re: Z motor noise due to loss of X-axis leveling
The bed leveling issue having squish on the right side and good 1st layer on left side of the print in my opinion is a Prusa firmware problem. You can make the bed physically level to the Y-axis rods but the auto mesh leveling will always cause the right side of the bed to be higher. If you try the fine tune compensation it won't entirely correct the leveling. Hoping the firmware gets updated soon because it's an annoying problem among others.
MK3 Kit, Designed, built 4x4 CNC Plasma Cutting Table, Motorcycles Bigdogbro's Adventures
http://www.youtube.com/channel/UC5djrxBeeOKB9_6rHnn6G8A
Re: Z motor noise due to loss of X-axis leveling
The bed leveling issue having squish on the right side and good 1st layer on left side of the print in my opinion is a Prusa firmware problem. You can make the bed physically level to the Y-axis rods but the auto mesh leveling will always cause the right side of the bed to be higher. If you try the fine tune compensation it won't entirely correct the leveling. Hoping the firmware gets updated soon because it's an annoying problem among others.
well, this make's me feel a little bit better. this thing is driving me crazy and I thought that was caused by me. is it a recent issue are they aware about it?
Re: Z motor noise due to loss of X-axis leveling
I'm not sure it's the same thing, but I noticed something similar when assembling my printer. The left lead screw nut was a loose enough fit on the lead screw itself that gravity would cause it to slide down the screw when the motors were unpowered. I "fixed" it by roughing up the very edge of the threads on that left nut. That added just enough friction to keep everything in place even with mild downward pressure on the X axis, at least for now.
Of course, be careful if you decide to do the same. I (slightly) physically damaged a part of the printer, any consequences are on me.
Re: Z motor noise due to loss of X-axis leveling
You might need to drop down the Z-axis another 5 to 10 microns and also attempt the bed leveling 4-points fine tune.
90%+ IPA to clean build sheet
Try 5 degrees hotter on the 1st layer.
Slicer:
Slow down on 1st layer to 20-25mm/sec
Try 5 degrees hotter on the 1st layer.
MK3 Kit, Designed, built 4x4 CNC Plasma Cutting Table, Motorcycles Bigdogbro's Adventures
http://www.youtube.com/channel/UC5djrxBeeOKB9_6rHnn6G8A
Re: Z motor noise due to loss of X-axis leveling
Ironically, I had this issue on the An*t A8 which the i3 mk3 replaces. I think the fundamental issue is that the weight of the stepper on the left hand side causes the Z axis on that side to creep downwards when the machine is off or steppers are disabled, or the right hand side to creep upwards, via leverage. Or possibly a bit of both.
I guess it should be possible to add start gcode which pushes both sides of Z right to the top, forcing the to be level, before starting the mesh bed levelling?