Repeated Bed Leveling failure
OK, how do I fix this?
Core One, does 49 points, and says the bed is not flat. I say yes to do the Z-alignment, the bed goes all the way down, then comes back up, and it does the points over again, and still fails. I have turned it off, same problem. I pulled out the print sheet, cleaned it well, cleaned the heating plate well, flipped the print sheet over. None of those fixed it.
Where in the build instructions do I need to go back to to check something?
RE: Repeated Bed Leveling failure
Best would be to reach out to support so they could walk through the issue and the steps to check to see what the possible issues could be
Shane (AKA FromPrusa)
RE: Repeated Bed Leveling failure
I have the same issue with my mk4s to core one + upgrade.
After lot of research I found that the new axis only moves 199mm when moving 200mm in the controls. The axis reused from the mk4s does move 200mm.
When doing a small print, it is not an issue, but when printing something large, the bed mesh will fail because the left side is about 1.4mm lover than the right side.
quick check: calibrate z-axis, with contro, move z-axis to 1, and check how far the trapezoid nuts are removed from the gantry. There is a noticeable difference between left and right.
RE: Repeated Bed Leveling failure
did you get it fixed?
OK, how do I fix this?
Core One, does 49 points, and says the bed is not flat. I say yes to do the Z-alignment, the bed goes all the way down, then comes back up, and it does the points over again, and still fails. I have turned it off, same problem. I pulled out the print sheet, cleaned it well, cleaned the heating plate well, flipped the print sheet over. None of those fixed it.
Where in the build instructions do I need to go back to to check something?
RE: Repeated Bed Leveling failure
This problem was vexing me for a while and I finally sat down to get to the bottom of it just this morning (trying to print: https://www.printables.com/model/36706-bed-level-test). I was able to resolve by doing the following:
- run z-alignment calibration, which lowered the bed to the bottom
- power off the printer
- using hand rotate the three z-axis lift rods to make sure each point was as low as it could go
- loosen the bolts on the trapezoid nuts so they are just barely snug. I found many posts that said they cannot be too tight.
- power back on and re-run z-align calibration
Then the printer finally passed the 49-point check.
I did all of this after detaching the trapezoid nuts and verifying that they could freely move, then reattached them using the non-threaded holes. Not sure if that makes a difference, but it allows some play between the plate and nut.
RE: Repeated Bed Leveling failure
This does not solve it for me, I already checked that and does not work for me because one thread is moving less distance than the other two. If the leveling was wrong, the error would be the same on all heights, but that differs for me.
I measured this several times. Z-calibration, then with the controls I moved the bed 100mm, 200mm and max distance . all had a different error (but linear with distance) 100 => 99.5, 200=> 199mm 274mm=>272.5mm (I could not measure more precise than 0.5mm)
For the time being I made caps for on the bottom screws for that one thread motor, so sits high during calibration, and now it is always level on top.
meanwhile I'm waiting for help from Prusa.
This problem was vexing me for a while and I finally sat down to get to the bottom of it just this morning (trying to print: https://www.printables.com/model/36706-bed-level-test). I was able to resolve by doing the following:
- run z-alignment calibration, which lowered the bed to the bottom
- power off the printer
- using hand rotate the three z-axis lift rods to make sure each point was as low as it could go
- loosen the bolts on the trapezoid nuts so they are just barely snug. I found many posts that said they cannot be too tight.
- power back on and re-run z-align calibration
Then the printer finally passed the 49-point check.
I did all of this after detaching the trapezoid nuts and verifying that they could freely move, then reattached them using the non-threaded holes. Not sure if that makes a difference, but it allows some play between the plate and nut.
RE: Repeated Bed Leveling failure
This does not solve it for me, I already checked that and does not work for me because one thread is moving less distance than the other two. If the leveling was wrong, the error would be the same on all heights, but that differs for me.
Is your printer a kit or pre-assembled? There have been issues where one or more of the Z axis threaded rods have a different thread pitch than the others which can cause a problem like this. There are tools on Printables to measure this. If you can show support this is indeed the case, they will send you replacement motors.