Z is lost on initial print


Running following setup:
Prusa i3 MK3S+
OctoPrint 1.9.0 Python 3.9.2 OctoPi 1.0.0

I turn on the printer and start the printing job. I see that the first layer is printed really bad, I cancel the job via OctoPrint UI, remove the print and print again the same job (I do not change any settings at all). For whatever reason, the second time I print the same job, it goes without any problems.

I also restarted OctoPrint via UI and the same problem rises again. The same problem was on OctoPrint 1.8.3 too.

I feel like the Z is getting lost.


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Have you tried running in safe mode?


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Systeminfo Bundle

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Safe mode doesn't help.

octoprint-systeminfo-20230603145134.zip (105.9 KB)

Can you share the gcode file that is causing you the issue here? And maybe enable the serial.log, reproduce the issue and then share it so that we can compare the two to make sure nothing is being sent to the printer wrong.

Does the Z re-home in between the prints correctly? Perhaps the second print is not changing the Z height back down to where it should have been.

Here is the gcode:
Shape-Cylinder_0.25n_0.15mm_PLA_MK3S_3m.gcode (44.3 KB)

Z does re-home in between the prints and prior printing, there is always mesh-bed levelling.

I have enabled the logging and will post serial.log soon. I am waiting for the SD card to arrive so I can test this without OctoPrint. I really hope, that this is only the software problem and not related to hardware.

Here are some more photos:

Here is the serial.log:
serial.log (163.6 KB)

And this is the result:

Printer stopped two times while printing the model.

RPI port: OFF
Print from SD card -> OK

RPI port: ON
Print via OctoPrint from the same SD card -> Z is lost

There are two SD cards: one inside Raspberry Pi Zero and other inside the printer. Previous prints were done via Raspberry SD card and these ones in the photo via printers SD card.

Additional serial.log:
serial.log (103.8 KB)

And a print directly from OctoPrint?

Actually, we don't count that as SD card. We say: Print from OctoPrint. Just to prevent confusion with the printer's SD card.

I removed the Raspberry Zero from the MK3S+ and problem remains. Apparently, this is the problem with either the printer or the firmware. I believe, this started once I switched to 0.25 mm nozzle, but I am not sure. Case forwarded to Prusa Support.

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