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Live Z suddenly changed for no reason.  

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loadinglevelone
(@loadinglevelone)
Trusted Member
Live Z suddenly changed for no reason.

Experiences something strange last night. In between two identical prints the Mk3s suddenly decided to dig into the print bed.
Did a first layer calibration and had to adjust my live z from -780 to -530.  

All is well now again with the new live z value, but what could have caused this?

I've been using the printer at -780 for the lat 6 months and its been flawless at that setting.
The printer did not bump into anything during the last print.
The pinda probe is firmly attached and hasnt drooped or sagged or anything like that.'

But something cause a sudden change of +250 in height. Mysterious.

My printers: Mk3s / Mk3s clone with +upgrdaes (you know SPinda and all that good stuff) / Mini+ / Ender 3 v2...
Posted : 12/05/2020 9:55 am
loadinglevelone
(@loadinglevelone)
Trusted Member
Topic starter answered:
RE: Live Z suddenly changed for no reason.

OK now I'm even more confused. 

Changed fro smooth sheet to steel sheet and of course had to recalibrate first layer on this aswell. But here's the thing. The difference in new value for this sheet was only half the value of the smooth sheet. Go figure.

All is well with the new calibrated values though, but how come?

My printers: Mk3s / Mk3s clone with +upgrdaes (you know SPinda and all that good stuff) / Mini+ / Ender 3 v2...
Posted : 12/05/2020 10:46 am
loadinglevelone
(@loadinglevelone)
Trusted Member
Topic starter answered:
RE: Live Z suddenly changed for no reason.

Update:
The day after this happened, the live z value was back to normal and has been ever since.
I can only speculate as to why the z calibration suddenly changed, but my theory is that it had to do with thermals on the pinda.

On the day of the problem, I was running a batch of very small prints. None more than 20 layers in height - one after the other. Time and time again. So the pinda always stayed fairly close to the printer bed for hours on end, constantly heated.

Anyways - just a theory - but based on what other are saying about the pinda and heat, its my best guess.

My printers: Mk3s / Mk3s clone with +upgrdaes (you know SPinda and all that good stuff) / Mini+ / Ender 3 v2...
Posted : 29/05/2020 7:31 am
Neophyl
(@neophyl)
Famed Member
RE: Live Z suddenly changed for no reason.

Some of us are running modified start up gcode that makes sure the pinda reaches a set temperature before doing levelling.  This takes care of any problems like this.  On colder days though it does cause a delay in printing while the pinda gets to its stable temperature.

Have a look at Bob's site where he lists his start up code with comments.  He has the same process and its nicely documented.  http://projects.ttlexceeded.com/3dprinting_prusaslicer_gcode.html

Posted : 29/05/2020 7:52 am
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