Sudden problem with center point on mesh bed levelling
My MK3S started to behave strangely while performing the mesh bed levelling.
Usually it moves to all nine points, does the distance measurement on each point, and then starts to print.
However, since a few days there seems to be a problem with the center point. Sometimes the printer does the distance measurement at the center point, then the Z axis moves up and down by maybe one centimetre, and then the distance measurement at the center point is repeated. The other eight points are fine though, the distance measurement is as usual there.
The print is also fine, so I could just ignore that new behavior. However in my experience, new behaviors tend to become worse over time. So if there seems to be a problem with the center magnet, the PINDA probe, or whatever else, I would like to get it fixed it rather sooner than later.
What is does this strange Z axis movement on the center point mean?
Thank you! 🙂
RE: Sudden problem with center point on mesh bed levelling
That's normal behavior. Nothing to worry about.
RE: Sudden problem with center point on mesh bed levelling
It is normal as fushr says. This occurs when a measurment obtained is out of bounds.
I would check there is no play in your Y axis, bearing holders are nipped up correctly, rod holders are nipped up, no bed screws are loose.
After checking the above and resolving a .3mm bed variance has not happened again on my mk3s+.
Read this for the full sp.
https://blog.prusaprinters.org/prusa-tech-insider-1-mesh-bed-leveling_30817/
Tank you very much!
RE: Sudden problem with center point on mesh bed levelling
As I recall, what most folk have found when the printer has to retry the bed level like this is that the printer is on too bouncy a surface. Try adding some mass under the printer - - like a large concrete paver.
If the PINDA is a bit high, it can exacerbate this condition. I'd make sure the Live-Z value is between -0.800 and -1.500 for best results. Also, use the 7x7 point cal. It is just better. And 5 samples. A few extra seconds but far better bed level.
RE: Sudden problem with center point on mesh bed levelling
Thanks for your help.
The problem disappeared after a Z axis reset (the one where the extruder is moved to the very top).