Prusa MK3S+ desperation beeing trapped in "Z-Calibration enforced" loop
Hello,
for some weeks i can no longer use my printer because it immediately wents into an eternal loop of "Z-Leveling enforced" after the first 2-3 of the 9 reference points visited on the start of each job.
I tried to re-run the First-layer-calibration but this yields exactly the same result.
I attached a video of this operation because i have the feeling i can not exactly describe this in few words.
What is strange and makes me wonder ( you see in the video ):
- why this "crashing sound" when the Z-Axis reaches the top position
- why are the reference points the printer visits initially shifted to the left ( = larger space left right to the 3rd reference point?
What i tried :
- with disabled steppers manually align Z-Axis using a piece of paper beneath the nozzle ( there was like ~1mm difference in height between right and left front part of the print bed )
- re-adjusting the PINDA to be sure it is between 0.5 and 1mm higher than the tip of the nozzle
- re-starting the first layer calibration multiple times until realizing this would just not change the isse
I would be grateful is someone got an idea what i can do, because what i found so far here in the forums and for example in reddit posts
was not helping 🙁
Thank you,
bexxx
RE: Prusa MK3S+ desperation beeing trapped in "Z-Calibration enforced" loop
In your video you can see, that the right side hits the z-end stop quite a bit later than the left. Unfortunately your video does not show the next enforced z-levelling. Would be interesting to see if that’s the same on the next try. If so that would indicate a problem with one of your z-motors.
the sound when hitting the top is normal - no worries.
next thing: are the trapezoidal nuts mounted correctly, check the assembly guide.( https://help.prusa3d.com/guide/4-z-axis-assembly_168629 ) Is there anything else in the way of symmetrical z-levelling?
If at first you don't succeed, skydiving is not for you.
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RE:
Hello,
thank you for the quick reply; about the nuts - well i have the printer since 2020 and printed around 14 days in total according to the statistics. And for the longest time i did not experience this ( i build the printer from parts as i prefer this way to learn ).
Here a longer video starting with the First-layer calibration and the additional force z-calibration ( which will chain endlessly from then on ):
Is there anything else in the way of symmetrical z-levelling?
You mean if there are more problems besides what i described so far? No, this is currently the primary stumbling block i am aware of.
Maybe i can tell that the mount of the PINDA broke off and i repaired it using "fast-glue" ( don´t know if this is correct word ... ) and a hot-iron.
Sounds crude but i am quite confident my repair keeps the PINDA in the correct position:
RE: Prusa MK3S+ desperation beeing trapped in "Z-Calibration enforced" loop
Hello,
thank you for the quick reply; about the nuts - well i have the printer since 2020 and printed around 14 days in total according to the statistics. And for the longest time i did not experience this ( i build the printer from parts as i prefer this way to learn ).
Here a longer video starting with the First-layer calibration and the additional force z-calibration ( which will chain endlessly from then on ):
Is there anything else in the way of symmetrical z-levelling?
You mean if there are more problems besides what i described so far? No, this is currently the primary stumbling block i am aware of.
Maybe i can tell that the mount of the PINDA broke off and i repaired it using "fast-glue" ( don´t know if this is correct word ... ) and a hot-iron.
Sounds crude but i am quite confident my repair keeps the PINDA in the correct position:
Hello, so what id do is lower the pinda below the nozzle so you know its definitly reaching the bed before anything else just to confirm.
Please help me out by downloading a model it's free and easy but really helps me out https://www.printables.com/@Hello_474427/models
RE:
Ok, looking at the new video, I’d say the z motors and the z end stops are ok.
i think you are right about the PINDA, it looks to be where it should and the fact that your nozzle does not hit the bed when homing and probing indicates the correct height. You could do what hello suggested but the only thing you would gain is that you are sure nothing is blocking or jamming your PINDA measurements. Obviously you can not print with PINDA being below the nozzle. On the other hand,that’s how troubleshooting works, systematically eliminate probable causes.
One thing I wonder about is the homing behaviour of your printer. It homes x then y then z and then x and y again - that’s very strange, and has nothing to do with PINDA.
my next step would be a factory reset and self test and calibration wizard. If the behaviour remains it’s time to ask the PRUSA support guys via the chat in the shop (log into the Prusa shop with your credentials and wait a minute for the chat to appear.)
If at first you don't succeed, skydiving is not for you.
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RE:
Moin,
the z-calibration loops because when the axis is supposed to bump into the upper mechanical ends your filament throws the "measurement" a little off. The x-axis is then not parallel enough to the bed so that during the crossing x the difference between left and right exceeds the tolerated limit. Hence the loop. Plase unload the filament prior calibration. If that is not enough, please take of your spool holder and anything else on top you added, e.g. the cable ties on the left. Be aware, that the printer may trigger a calibration also during normal print when it assumes, it has been thrown off balance. As a consequence, the filament guide should be changed so that the filament does not apply any vertical force on the extruder anymore. A minor design issue on the MK3S(+) is, that is not clear which surface of the upper z-holder comes (first) into contact with the upcoming x-axis. In order to mitigate that and to be able to adjust left and right end stops just a fraction of a mm I added a vertical screw to each stop.
Please ensure, that no external vibration can disturb the calibration. If necessary, put the printer on a different solid gound prior calibration.
The "crashing sound" is pretty normal. If you assembled the printer yourself yous hould have observed this already.
The movement in x is probably shifted because the belt of the x-axis looks very loose. Please look how the lower section of the belt moves up and down when getting tension and loosing it.
RE: Prusa MK3S+ desperation beeing trapped in "Z-Calibration enforced" loop
Hello,
first of all - thank you for the additional ideas !
Had no time since my last post unfortunately, will see tomorrow
- PINDA - check ( set it below the nozzle ) -> will do so
- calibration with unloaded filament : interesting aspect @blauzahn, i will give that a try first
- avoiding external vibration - usually i have it standing on top of 1cm thick rubber on a shelf, but i will try it having the printer on my ( wooden ) floor to avoid anything
- belt tension - yeah i thought a little in this direction but so far was a little "lazy" to go further into that topic ( as my printer worked fine until like 2 month ago )
I give you feedback hopefully tomorrow how far i got 🙂
@blauzahn
yes indeed i assembled it, but unfortunately i had to make a longer health-induced pause after that ( so i did not remember everything ).
If i need a factory reset in the end i will do so, while from your observations based on my videos i probably have to re-adjust some aspects on the printer anyway.