Layer shifting after color change

I’ve only had my P1S since December and been seeing a shift in the X-Y axis when the printer is paused and resumed.

But on 2 occasions, I had an even worse effect: Once when at the beginning of the print, the head moved from front right to the rubbing area and the nozzle was too low so it scratched the whole plate (totally new).

And then it even did the whole rubbing ON the plate itself instead of the back!!!

I have to say that I am very disappointed… I opened a ticket 10 days ago and still no answer.

When I got the printer, I ran out of filament, so I changed and continued and it was perfect. I then made an update (don’t remember what the previous one was) and started seeing these weird behaviors. Currently have the latest: 01.05.02.00 (latest version).
Also checked the screw at the back, they are tight, PTFE tube moves freely and “Auto-recovery from step loss” has no influence…

Check your nozzle as this is an indication of it being bent.

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It’s not a unfixable deficiency where the printer just can’t do it. There is something wrong with your printer that should be fixable.

I have never had this problem and I have printed models that change color after a layer and others that change a few colors within a layer.

Thanks for your message.
If this would be the case, then it must be very bent and I don’t see it:

Well, I’m trying to get it fixed by Bambu Lab, but no reply from them… since 10 days!

Support response time has been a problem for them for a while and the A1 issue made things even worse. They said they are trying to resolve it and improve response time, but for now all you can do is wait or follow up to ask how long it will take them to respond.

Often “weird behaviors” after a firmware update (on any device) can be corrected by restoring factory settings. You will lose any filament calibrations stored on the printer, but a Factory Reset and printer re-calibration may correct your troubles.
image

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I was thinking about that today while posting, actually! I will try it now.
Calibration alone brings nothing, this I can already confirm.

OK, so Factory Reset brings nothing…
Then I downgraded to version 01.04.02.00, still no change.

What’s interesting is that if I pause it once, then there is an X/Y (-0.9mm / +2.4mm) shift, if I pause it again, it continues from where it was supposed to continue…
Seems like it looses its reference on the first stop, but on the next pause it keeps the reference…

It seems like it is most likely a hardware issue, not software. Have you done all the maintenance like belt tightening, cleaning and all the other things they mention in the Wiki?

OK, so I found out what it was and where it came from.

3 weeks ago I printed these dust covers for the X-Y motors:
https://makerworld.com/en/models/170634#profileId-187309
(they have since been taken down for very good reasons, but I had bookmarked them…)

After reading this post https://www.reddit.com/r/BambuLab/comments/10jvjrj/comment/j5rz43b/ , I realized that the P1S was homing without end-stop switches (even my old Ender 3V2 had some!)… And the covers where basically creating an offset when pausing in the back left corner.

So if you ever find a shift, it is probably because your machine loses its reference. So either you have to add a homing action of X-Y after every time it goes to the back left corner or find out what is creating the shift.

It still doesn’t explain why my plate was scratched, but now I understand how critical it is for the motors to move freely, without missing steps.

Thanks to everyone.

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It’s more so 4/10 times it fails or does something it’s not supposed to and the other half it’ll function properly…

We had an issue like 2 firmware versions ago, where a specific slicer setting caused the tool head to stop every couple layers and purge - retract - feed - purge - resume… Changed some settings and it went away but I can’t remember exactly the feature, but I think it was something with wipe on loops.

I’ve experienced the X1C do crazy things… Just the other day, the bed was lowered near the bottom due to completing a tall print previously and yet when starting another print it lowered and made the grind sound hitting Z limit…

This was supposedly addressed and fixed in past firmware updates but it randomly happend and doesn’t always idk…

I can confirm that. I printed the same dust covers and I had the same issue with layers shift.
Don’t use dust covers and be happy ))

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@umaiku Thank you very much, if I had come across the post with the covers earlier. These were the reason why the layer shift occurred.

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OMG!!! You just solved a problem that has started recently and was driving me crazy. Whenever I printed anything with a filament change with my P1S and AMS, I would get a slight layer shift and had no idea what was happening since it was not happening before.

Thank you very much for this!

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Thank you very much you just helped me out after a long search <3

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I’ve been going out of my mind with first filament layer shift the last week… been happening on most of my prints and I do a lot of multicolour.

I have just downgraded the firmware and the first print seems okay so far… wondering if there is an issue in the latest firmware to be honest