Can't get my nozzle to go low enough to the bed A250

I have calibrated my bed level every way possible. Manual, Automatic, Heated, not heated, 3 points, 5 points etc. I’ve confirmed that the bed is screwed on as it should be.
I’ve levelled it close to the bed, single sheet of paper under a clean nozzle. But when I start my print the nozzle is about 1mm of the bed. I’ve even adjusted the Z-height, before and during the print start, to the max of -0.5 and its still nowhere near close enough.

Has anyone else had this issue?

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I had the issue that the machine ignored touchscreen-entered negative Z-offsets during print - did a 11x11 “manual” calibration before and attributed it to that… Have yet to verify it happens also with a touchscreen-initiated calibration procedure… seems it does from your report.
My solution: Level the nozzle a bit too low (basically touching buildplate without calibration card inbetween and then work with positive offsets.
Am on 1.13.2. firmware.

Just in case you were not aware. One of the firmwares started saving the z-offsets to eeprom. That change also introduced a bug where it does not (always?) save the adjusted z-offset set via the touchscreen, causing the setting out of sync with reality. This happens if you use the settings button to adjust z-offset prior to pressing start (could be other situations as well). There are several threads about this, so you can look it up for more details.

It has been reported as a bug by someone several firmware updates ago… This same user also (can’t remember whom to credit) came up with a working workaround which goes something like this:

  • start a temporary print (as small as possible, because I think you need to “finish” it) and while it prints, adjust the z-offset to zero (if it prints mid air, let it finish). This will save the offset as zero.
  • restart the machine .e. a full “cold boot” (this is required to get rid of any out of sync saved offsets)
  • start the calibration process normally
  • it should now calibrate correctly without erraneous compensations.

If you need to adjust the z-offset on the fly for e.g. switching between PLA and PETG, or getting a perfect first layer, do it ONLY AFTER the printing has started. I print either a large enough brim or several lines of skirt to see that the layer is solid but not overflowing and adjust at this point if needed. Whatever you do, do not change the z-offset prior to pressing “START”, or you will end up in the situation you described. It used to work correctly in the older firmaware versions, but not the later ones.

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Thanks for pointing this out - but actually that’s exactly how I do it (it never occured to me to adjust Z before the print). My procedure is: Start print, have a skirt or brim and use that to live adjust Z offset. But that’s exactly where I was unable to use negative ofsets.

That was me. :slight_smile:

I am not entirely sure as of yet, but I think that it is fixed in 1.14.2. I noticed that there is a difference in the Calibration sequence as well. It no longer shows an offset when you are setting the Z Offset at the end.

I remember someone else saying the same. I can adjust it downward to max -0.5mm and following the described procedure I’ve been able to start from zero after calibration (at some point it was several mm in the air and refused to go lower…). What firmware are you on? I just checked mine and it is 1.13.2 (and the original before that, which worked fine)

Thank you, it was a valuable tip that has allowed me to use it at least for most part.

Since I ran into these issues upgrading from the original firmware to 1.13.2 (just checked what I was on) and researching the forums I’m very very hesitant to screw it up even more… Reading some of the comments about the quality of coding, I’m even more scared (I’ve worked in IT for 25 years so I have seen a lot from real professionals to absolute disaster, and what I see now leans more toward the latter to say it nicely). I noticed I nowadays have to spend more time on the forum trying to learn about the issues and solve things, than actually using it.

Not sure of the status of the very latest update, but one of the later ones also seems to mess up the laser. Not that the original laser can be used for cutting much, but it has worked for simple etchings. I hope there would be one update where they would solely focus on fixing all the open issues before continuing to introduce other features (and issues…).