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).
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…
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.
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?
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.
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…
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.
I just recovered from this highly frustrating issue.
In my case, after a clog cleanup that required the cutter arm allen screw to be released and retightened, the cutter arm was hitting the side of the middle housing. The cutting process started making a loud noise, but since I had the printer for only a week, I didn’t know if this was expected or not.
So, the filament was being cut, but when the motor pushed the head to the cutter knob hard, it disturbed the X-axis positioning.
After much research and observation, I diagnosed the issue and disassembled the cutter arm several times till we found an orientation (tbh by luck) that it was able to push clear the housing.
This was a nightmare. Bambu could not help at all, but now they are providing middle housing cover and a new cutter arm.
I have the A1 Mini and am having the same issue, layer shifting during color changes. I am running Firmware 01.03.01.00 and AMS Firmware 00.00.07.93.
If I print one frog there is a slight shift, if i print 10 frogs it is much worse, and if I turn off Auto-Recover from Step Loss it is even worse.
