Z offset changes after every print

[frink 0]

Hello, i have

 

Two ender 3v2 modification:

2 z axis

bltouch

upgraded springs

marlin software 

 

One ender 3 s1 (everything original) 

 

And having problem on all printers, after making mesh and setting z offset seems everything ok and prints are perfect, but if i try launch another print z offset already changed and nozzle touch the bed. Z axis perfectly calibrated, bet tight and not moving, x axis stable.

 

Any suggestion? 

[GregValiant 1,251]

The Z-offset is typically a printer firmware thing.  Are you using a plugin in Cura to set the Z-Offset?  Maybe there is something in your startup gcode that affects it?

Is the actual number value of the Z-offset changing or is the printer simply doing something different (even though the number is the same)?

[frink 0]

Im using cura ant prusa slicer but dont use any z offset settings on it. 

 

The number of z offset are same but nozzle push plate hard after print. Sometimes even after setting z offset with paper everything ok, i press home and try check one more time and wrong.

[GregValiant 1,251]

The endstop switches are the same so try swapping the Y endstop switch with the Z endstop switch and see if it makes a difference on at least one machine.

The Endstop switches aren't very "repeatable".  When you auto-home and level the bed and then the printer sees the "G28" in the StartUp gcode it homes the Z again.  There is no guarantee that the "Z = zero" position is going to be the same location as when you leveled the bed.  It should be OK with ABL but I gave up with my paper leveling and my start gcode has G28 X Y so it leaves the Z where it was during leveling.

[frink 0]

But im not using z stopper on any printer, i use only bltouch. I should install z stopper and use bltouch at the same time? 

[GregValiant 1,251]

No, don't do that.

Are you slicing once and then running the same gcode on different machines?

Do you have a different machine profile for each printer?  I don't think I've ever seen a Z=0 in a gcode file so something is going on to make the nozzle hit the bed.

 

Load a simple model (a calibration cube will work) and set Cura up to slice.  Use the "File | Save Project" command and post the 3mf file here.

  Maybe something will jump out.

[frink 0]

I think i solved problem: 

i was using bltouch before every print in gcode, now i calibrate once and leave it alone, now i have ~10 prints on each ender 3v2 and prints are good. 

 

But i having other issue about ender 3 s1 which firmware i should use? I dont find any similar marlin like i use ender 3v2 (it has good interface for leveling) 

 

I found this, is this good for ender 3 s1? https://github.com/mriscoc/Ender3V2S1/releases/tag/20221002

And if this firmware are good i should use UBL or without UBL? 

[Stewered 2]

Save the Z offset: On the Ender 3 V2's new mainboard, the printer automatically stores its onboard memory to the loaded microSD card. Some users have pointed out that the Z offset figures only save to the printer vinyl when the microSD card is plugged in.

Edited January 25, 2023 by Stewered
some thing wrong i sole the problem.