I have the same problem, different model files, different slices, different filaments (mainly Bambu Matte pla, the one in the picture is Bambu Metal pla), different speeds and speed modes, the pictures are from the same slice, the upper body was printed in silent mode.
Of course I did the maintenance first after I noticed the shifts on large prints, I also had the circular noise that felt a little better (but didn’t disappear) with the belt tension readjustment, but it didn’t change the shifts.
Hi Everyone,
Is there a solution to this issue. I have had the last 3 prints all having significant layer shifting. Different files and different models. I’ve given the machine a proper maintenance clean, including the rods etc… Not sure on the proper procedure to tension the belts other then what is suggested in the youtube vid posted at the beginning of this thread
Not sure how to post images. …I got an error saying i can’t attach images to this post.
Cheers,
Hem
mine has been doing the same i tried losening the tension belts and it kinda works but it always get right back to layer shifting
how do you llosen the belts on x1c?
There is a link way up in this thread explaining the steps of proper maintenance. And the Bambu Lab wiki has a good guide also.
Hello there, I have the same issue. For now, it happened while printing with Sunlu ABS using the Generic ABS profile. I have Automatic-recovery from step loss already disabled and the volumetric speed for this profile is 15.
I have already done all the maintenance tasks shown in the video. I’m scared by the sound coming out of the printer when this problem happens. The printing shifts, and I think something can break because the head hits the limits and forces to go over.
Any help would be appreciated, thanks.
Similar situation here, with 2.1mm layer shift in both X and Y. This was about 20 hours into a 32 hour print using Bambu PETG basic.
This was the 4th or 5th print after my most recent maintenance, during which I replaced the hotend assembly and re-tensioned the belts (followed by re-calibration and self test.) Lead screws were last cleaned and greased 35 days ago, and the carbon rods were cleaned 19 days ago. Y axis rods were also cleaned and re-lubricated at that time.
This was a large print (659g) that followed another large print earlier this week (550g or so). That previous large print after the hotend swap looks fine.
I’ve put around 40 kg through this printer without any meaningful layer shift or other issues that weren’t my own fault. Sadly no video
Very interesting thread. Same issue in my end.
Can somebody with and without the issue try the following please: move the print head on x axis and check if there is a slight movement on y axis as well?
Did somebody try to replace the motor?
Thanks and kind regards
Holger
Had this issue right now as well, glad for the responses here - I’m definitely going to try the belt tensioning, I’ve had my X1C for about 5 months and have put 1,800 hours in prints on it and have never done it so I’m probably due. What’s weird with mine is that I have 8 sets of 2 models printing on the build plate, and about .5" up it shifted about 1-2mm, I’ve never seen anything like this happen with this printer yet so it’s quite a shock. I’ve printed 32 of these desiccant spool pods so far and they’ve all come out perfectly with the new PETG HF, so it’s not the model. Hoping it’s the belts, wish me luck!
Were you able to solve this issue? I’m suddenly getting layers shifts on X1C after 6 months of use. It shifts about 1 mm in one direction (usually X) and then shifts back a while later. Strange.
I can’t say for absolute certainty if what I did actually fixed it or not, but since I posted my pics I did the full maintenance routine including belt tensioning and oiling the belt casters, basically every maintenance step that can be done on tthe X1C (also installed the BIQU panda jet) and since then I’ve not had the issue, and have printed several more of those cores and others items including tall items without issue. That was a few weeks ago so hard to say if it fixed it or it’s some intermittent thing. But it was good practice to do anyway.
Okay, I spent a lot of time getting suggestions from tech support and adjusting printing parameters, including: speed, retract, Z-hop, infill pattern, nozzle temp, flow rate… I tensioned the belts a couple times. Nothing made any difference to the layer shift problem, which I was constantly getting on X1C, but never on A1 mini. Then I noticed that it didn’t happen when I printed a smaller quantity of parts. With 14 parts on the bed, it didn’t happen. With 18 parts on the bed the layer shift was bad. So now I just reduce the number of parts being printed at a time, to avoid the problem.
Interesting. How much plastic is used when you print 14 vs 16 parts? The most notable example of the issue I’ve experienced was a 669 gram print with 9 parts. (I said 659 g above, but re-opening the model today it comes out as 669. Don’t know if that was a typo or something else.) The shift occurred at 20 out of 32 hours, so probably around 400-420g of plastic printed. Or 140 linear meters of filament printed from the spool.
I’m wondering if the issue is caused by some counter overflowing during large prints.
I 2nd this. 
also from experience, there’s no repeatability when it comes to power loss recovery.
I’ve found that to be fully ineffective as well filament error triggered stoppages. I’ve sent a ticket regarding this to Bambu support and was sent to provide further troubleshooting steps and supply video.
I don’t have the time to pull a printer off and do it so it’s on me i guess… My workaround has been after a machine triggers any stop 
due to an alarm 
I’ll resume printing then force pause immediately. Then it’ll be a user triggered pause then I’ll resume and wallah, no layer shift.
Support insists that something is obstructing the toolhead when resuming a print and wanted the video to be overhead (bird eye) view of the printer to see. I also provided printer logs so if any object was causing the shift I’m pretty certain I’d know or hear it and quite frankly that’s just idiotic to think about being the cause of layer shift.
My theory is in correlation to a previous mention sometime ago when a user suggested it involves the power input (amps) to the stepper motors being low then suddenly being energized causing steps to be lost but not recognized by “step loss recovery”
Now step loss recovery does in fact work as I recently had an incident of a failed support on a 90 deg overhang. The top surface was warped so as the layers continued the nozzle was dragging which the toolhead then raises, zeros origin and resets where it left off and worked perfectly the remainder of the print.
Sorry for such a long explanation and scenario but these features have been a constant struggle throughout the development of FDM printing since the beginning. Layer shift is just a phenomenon error that’s yet to be 100% solved by 1 simple solution.
Best of luck
The part is 130g so 14 parts is almost two spools and 18 parts is more than two spools. I’m using the AMS to supply enough filament to keep going. I’m not sure if that has anything to do with it. The layer shift starts to occur very early in the print.
I ran exact file yesterday and it worked fine. I changed 2 filaments out of the 4 and I start getting layer shifting. I performed a maintenance on it today and tried the file again, and it still shifted. I have enabled Auto-recover from step loss and now trying a single color. Any suggestions appreciated.
