[Chiuso] Re-calibration show slightly skewed axes  

Re: Re-calibration show slightly skewed axes

do you use the actual firmware (3.0.12-RC) ?
there you can scroll down at the support menu to "XYZ cal. details".
if you push once, you'll get three values for the "Y distance from min": left, center and right.
if the left, center and right distances are equal, you've got a perfectly aligned printer, while I guess that a deviation below 0.1mm = 100µm should be sufficient.
if one value is to low, for example the right value (then the left value will be higher than the center one), alter your alignment in the way that the right edge is getting closer to you.

if you push a 2nd time, you'll get a value for the skew in degrees (eg 0.00°).

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why did this happen to you: maybe because previously your alignment were right at the edge between "perfect" and "slightly skewed".... and if you've removed afterwards a sticking printed part from the pei sheet, where you needed to apply a little bit of force to get it off, you might have "skewed" the whole printbed into the direction where the printer regards it as slightly skewed.
so make sure that there is as less clearance at the y-bearings (and the zip ties or u-bolts) and that the screws with which the printbed is attached to the y-carriage are tightened enough. but take attention: due to the very tiny amount of threading inside the standoffs, you can easily damage them.
in Germany we have a saying: "nach fest kommt ab.", which literally translates to: "after tight follows off".
so it would be a good idea to fix the screws and the standoffs, after a perfect alignment, with loctite stuff. even acrylic based nail varnish will do the job.

Re: Re-calibration show slightly skewed axes

do you use the actual firmware (3.0.12-RC) ? there you can scroll down at the support menu to "XYZ cal. details".
I'm not a big fan of putting Release Candidate software on device that can permanently damage itself on software glitch, so I'm still on 3.0.11. Being software developer myself I'm painfully aware that RC usually stands for "we think we fixed a bug, but no-one really is sure how, so we'll just put it up here to see if anyone catches it". That does sound as a good option to check when 3.0.12 goes stable.

On side note, I would love to see Prusa use semver on their versioning scheme. But I digress.

why did this happen to you: maybe because previously your alignment were right at the edge between "perfect" and "slightly skewed".... and if you've removed afterwards a sticking printed part from the pei sheet, where you needed to apply a little bit of force to get it off, you might have "skewed" the whole printbed into the direction where the printer regards it as slightly skewed.
so make sure that there is as less clearance at the y-bearings (and the zip ties or u-bolts) and that the screws with which the printbed is attached to the y-carriage are tightened enough. but take attention: due to the very tiny amount of threading inside the standoffs, you can easily damage them.
in Germany we have a saying: "nach fest kommt ab.", which literally translates to: "after tight follows off".
so it would be a good idea to fix the screws and the standoffs, after a perfect alignment, with loctite stuff. even acrylic based nail varnish will do the job.

Plausible. I have re-aligned Z frame, it was off by 0.3mm. I did not however remove or re-tighten headbed - visual inspection of U-bolts show that here is no space between them and X-Y frame, so re-tightening them should not have effect (manual even warns against excessive force, as it can deform bearings itself). At this point removing heatbed seemed counter-productive. Should problem arise again, I will check these.

Thank you for help.

Re: Re-calibration show slightly skewed axes

...
I'm not a big fan of putting Release Candidate software on device that can permanently damage itself on software glitch, so I'm still on 3.0.11. Being software developer myself I'm painfully aware that RC usually stands for "we think we fixed a bug, but no-one really is sure how, so we'll just put it up here to see if anyone catches it". That does sound as a good option to check when 3.0.12 goes stable....

I can see your point here, but this isn't handled by everybody in the same way.
prusa even "released" the 3.0.12-RC2 to the public with this thread. and since then (16 days), not even a tiny bit has changed at the github.

and by the way, I've installed the 3.0.12-RC2 since approximately two weeks at my MK2, without any issues.

Re: Re-calibration show slightly skewed axes

I can see your point here, but this isn't handled by everybody in the same way.
prusa even "released" the 3.0.12-RC2 to the public with this thread. and since then (16 days), not even a tiny bit has changed at the github.
I agree, yet I choose to err on the side of caution.

I'm not sure if damage caused by using RC software would be covered by warranty, and Mk2S is a bit too expensive toy to experiment 🙂

RE: Re-calibration show slightly skewed axes

I recalibrated my MK3 a couple of days before I got the MK3S MMU2S upgrade because of first layer issues, it was perfect calibrated.

Yesterday I finished my upgrade MK3S MMU2S and ran wizard calibration. Now it say " X/Y axes are slightly skewed". I know the printer will compensate for this during prints, but I want to get a perfect calibrated printer. I have follow two guides of this issue, but still skewed.

If I understand correct this may be like this.