Inconsistent First Layer / PINDA Calibration Issue
I have been struggling with the problem for a while now and have been able to narrow it down.
To the problem: Since unpacking the MK3 I struggle with the problem that the print of the 1st layer is very good in some places and I have a good closed layer, however, just as often the print is very bad and the 1st layer is very "stringy" and does not adhere well. The problem occurs especially in the middle of the heatbed. I tried a lot here, repositioned the PINDA probe and restarted the calibration process several times. The Bad Mesh calibration was adjusted but the inconsistency occurred again and again.
However, I could now see that the problems seem to happen only in the first print. If I abort the first print directly at the start and start the same print directly again, the PINDA probe seems to measure everything correctly and I get a great 1st layer over the whole print bed.
Does anyone know the problem? Is the PINDA probe to blame here?
Re: Inconsistent First Layer / PINDA Calibration Issue
Hi Alexander,
the Pinda probe is affected by thermal drift...
this is why Prusa integrated a thermistor with the pinda, to measure the temperature...
there are various ways of addressing this...
BUT putting that to one side, ....
It sounds to me, that If you abort a print and restart the print immediately, your printer reheats with the pinda, near the heatbed., and works successfully,
At the end of the print, your extruder and associated Pinda, is now much higher,
Starting a new print with the PINDA in mid air, reduces the heating effect from the heatbed, and it is likely that your PINDA Sensitivity changes, when you start the new print, this changed sensitivity changes the first layer level, and gives a bad first layer.... so you stop the print, clear the surface, and restart the print, with the Pinda close to the heatbed... where the Pinda heats up more, and the sensitivity changes...
so my suggestion... always start the print with the Pinda at the Home position (Close to the Heat Bed), see if this resolves your issue.
Alternatively, always start with your extruder well above the heatbed, re adjust your live Z for the pinda sensitivity at this level, and remember, if you get a failed print, that you should raise the extruder to the start position in mid air, to cater for the thermal effect...
This is a process I learned on My Mk2, and I apply it to my Mk3 as well....
Starting in Mid Air, makes it much easier to get the build plate in and out without scratching it on the nozzle
regards Joan
I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility. Location Halifax UK
Re: Inconsistent First Layer / PINDA Calibration Issue
Thank you for that one,
works really well. I now let the print head drive into the Autohome position before each print and let it warm up with the print bed. Since then the autocalibration before each print works fine and the print looks really good.