Filament change during a print results in layer shift

Bambu Lab P1 Series Troubleshooting
1

Hello,
This happens all the time. If in a middle of a print you have to change a filament (not using AMS), after loading new filament and resuming a print - it resumes and creates a layer shift. In other words - it resumes, but X and Y coordinates are shifted towards left deep corner for about 0.2-0.4mm.
And no, this is nothing to do with me waiting for too long and printed object already cooled down and shrinked etc. Nope, the change is done immediately.

I have a feeling that printer is not able to get the nozzle back to the exact same location it was before the filament ran out.

P1P, latest firmware.
Please advise!

6 Likes
2

There are reports on the forum about this.
If you are inserting a pause at layer in the slicer, instead of that insert custom code
M400 U1 ; pause and wait for resume pressed
G28 X ;home XY
M106 S255 , restart part cooling fan

If you want to make this the default behavior with ā€˜insert pause at layerā€™ you have to modify the printer profile. In printerSettings go to ā€˜Machine G-codeā€™ and scoll down to ā€˜Pause G-codeā€™. In the field should be ā€˜M400 U1ā€™. Add the other 2 lines. Save as copy and use the copy to slice.

3

Sorry, i am not fully understanding how this relates to my question. I am not trying to pause at layer. Printer pauses itself whenever filament runs out.

4

You will have to wait for a firmware update then. There appears to be a bug in the firmware that causes these layer shifts, it also happens with manual pauses where it can be fixed by the g-code posted above.
For automatic pauses due to filament runout, there is no solution currently.

5

Okay, so the filament runout sensor is useless unless the firmware gets updated and there is nothing one can do about it right now. Thank you so much for the answer.

1 Like
6

It does not happen with the AMS at all for some reason. But yes, unless its fixed, in that case I at least do not know about a workaround, doesnā€™t mean there is none, just I donā€™t know it

7

Can confirm, my filament just ran out 7 hours into an 8 hour print (No AMS), replaced it, layer shifted a few mm. Extremely frustrating.

2 Likes
8

I also have the issue. I ran out of filament and when I resumed it shifted. You can clearly see in the photos that when the print resumed it had shifted about 1mm to the left.

image

image

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9

Hoped todays firmware update would resolve it but thereā€™s no mention of this problem!

10

I would be nice if the firmware release notes gave more details.

Even better would be if there was a GitHub repo for the firmware so that all issues were tracked in a way that was visible to users and we could see what was reported and what was fixed each release.
GitHub repos donā€™t have to have source code. There is a Handy repo just to use for issue track.
http://GitHub/BambuLab

1 Like
11

Iā€˜ve tested this after upgrade my P1P to the latest version. But the layer shift problem is not solved. For now thereā€˜s no reason to upgrade. :roll_eyes:

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12

Bump! The same thing happened to me; 4 hours into 5 hour print and layer shifted after filament change on P1P. This needs to be addressed ASAP. Very basic 3D printing necessity.

2 Likes
13

Did a little test - not sure if that is reproducable with same success, but here it is.

  1. Print stops due to filament has ended.
  2. Instead of using filament ā€œloadā€ feature, simply heat the nozzle, and while extruding, push the filament in and continue to extrude, extrude, extrude till new filament starts to come out of the nozzle.
  3. Resume the print.

I tried this once with quiet a complex print and succeeded.

Of course, this is not how it should be. And i am not even sure this will always work, but I guess till we have a firmware fix, at least worth a try.

2 Likes
14

Donā€™t use Load/Unload, use th extrusion arrows, then no layershift. The bug is still present in the firmware, which gives a layershift, if you use Load/Unload when changing filament !

1 Like
15

Iā€™ve got a response to my support ticket from Bambu Lab:

"I am sorry to see that you are experiencing layer shift problems, but this is currently a bug that our colleagues are working to solve.
We apologize for the delay, but it will be fixed in the next firmware update. "

So, at the moment we have to use on of the workarounds and hope, that Bambu Lab will solve the issue soon. :slight_smile:

16

I am pretty sure they will. Its not a dealbreaker gladly with the workarounds, just a bit less comfortable.
Just make sure to add a pause before the filament runs out :slight_smile:

1 Like
17

I agree, this is what I have been doing. I find it easier to use this method when loading new filament anyway; the current autoloading method is bugged and laggy.

18

So if we do these steps, will the extruder still wipe the nozzle once you hit resume/play? The one time I did the unload/load routine, there was filament dripping down from the nozzle when I hit resume. Fortunately it wiped the nozzle before printing resumed,

19

only loading is causing it, unloading still works fine

20

Still a lot of problems. Cant use load/unload at all. If print pauses and I try to Unload, the printer says its busy, but preform unload action anyway. Display doesent showing the ā€œdoneā€ button so after unload im stuck. Only way out is to stop the print and restart. FIND A FIX.
Im not happy when updates makes it worse. Thats only bad technican fault.

1 Like