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Unresolved Z-axis offset not being respected?

Discussion in 'Troubleshooting' started by PrintingAlex, May 22, 2021.

  1. PrintingAlex

    PrintingAlex New Member

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    I just got my printer and tried a print, much to my expectation the bed wasn't where the printer thought it would be, it was trying to print like 2 inches away from the bed. So I adjusted the Z-offset so that the gauge was having a little resistance. This was +11.3mm.

    I went and printed again and much to my surprise, the C2 rammed the print bed into the print head and continued to do so until I turned it off. What's the point of the Z-offset adjustment if the printer doesn't respect what was set?

    I tried +2, 0, and -2 and all three jam into the print head. I now have some pretty decent divots where the print head melted the plastic bed. I don't want to play a guessing game here, it should understand where I set it to and not add additional values to the saved offset.

    I even went to the "Fine Tune Z-Offset" wizard and it worked for the test lines there, I ran test lines until the bed was at -7mm. I saved it, and then went to do a print of the bed leveling spiral test. The print bed went right to the print head, and nothing was extruded because the bed was right on the nozzle, it seemed to move fine but had no space for the filament. So, I went back to the fine tuning wizard and adjusted it until it was at -8mm, maybe -8.5mm. Once I confirmed the lines were good -- which is weird since -7mm didn't work on the same side that it once did -- I went back to print the spiral again. This time the bed tried to go past the nozzle.

    I am completely dumbfounded.

    I tried looking at the terminal through the Octoprint web portal to see if the printer log tells me where it expects the bed to be and where it is, but I had no such luck.

    Any ideas on how to get the printer to respect the offset?
     
  2. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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  3. PrintingAlex

    PrintingAlex New Member

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    Yes! Thanks for the reminder, I meant to post my Firmware version but failed to do so. I am on 2.0.0-c2.6. It's what the printer pulled over WiFi. I just checked for updates now to pull that number and I'm currently up to date. I'll do some digging but it doesn't seem like this issue has been reported in that thread yet? But I just skimmed it for the time being, I'll take some time in the very near future to read through the posts.
     
  4. narmentr

    narmentr New Member

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    I just inherited two C2 machines at the school I am teaching at and am having the same problem. I did a test print and it worked fine. Went through the update process for the firmware and now it is doing exactly as you describe. Just buries the hot nozzle into the build plate no matter what the z is set at. Any news on this or luck fixing it?
     
  5. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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  6. PrintingAlex

    PrintingAlex New Member

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    On my end, no. I tried the steps that were originally shared here with no success. I ultimately ended up returning it.

    This is absolutely mind-boggling to me. This wasn't some canary/dev/dogfood/beta build. This was the latest "stable" build available and the fact that the firmware still has a fatal print error nor has the firmware been pulled after 4 months is pretty amazing to me and makes me glad I returned mine.

    The FAQ link you originally sent wasn't helpful. I should have absolutely gotten back to you then, maybe we could have gotten this fixed before narmentr (and likely others) had the same issue but I just felt defeated.

    That entry into the FAQ just says that there's no fix. We're literally trying to get a fix, and the solution is to read the FAQ that says there is no fix and implies there is no urgency for a fix? This also doesn't answer my question, or really poses a new one. How do I check the wizard? When I saved the offset after the wizard it showed it as a negative value I set on the confirmation screen, and when I went back to adjust it again it was still the negative values I set. So my printer never seemed to store it as a positive (but maybe read it as one?). So how I can see if the value is stored incorrectly?

    I should have absolutely gotten back to you then, maybe we could have gotten this fixed before narmentr (and likely others) had the same issue but I just felt defeated.

    I don't exactly know what the staff member title means for the community - as I notice another member has this title but says they are not employed by Robo3D - but I hope you're able to take this frustration up to Robo3D in a capacity that I cannot and get them to care about their product a bit more.
     
  7. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    Robo has not had any new printers to sell in some time and there is no real way for a fix to come from them. We are fortunate that they are continuing to support the cost of the forums so that we can help each other. Forum staff are all printer owners and users. None of the Robo employees frequent this forum at all. It is all run by folks like yourself. Staff merely means we are the moderators for the community forum :)


    So ultimately the "fix" is to stay on an older version of the firmware in many cases.
     
  8. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    There is a way via the LCD to see what values are stored in the firmware.
    I will need to go over to our shop and take a look to get the exact steps.
     
  9. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    OK, sorry for the delay :)
    To see what is stored in the EEPROM for the Z offset follow the menus like so:
    1) Util
    2) Option
    3) EEPROM
    4) Home offset

    You should see your predefined Z offset stored in there (and you can edit it if you like).
    This should be a negative number because more negative is further from the bed and if it crosses zero into the positive numbers those would drive it into the bed.
     
    #9 mark tomlinson, Oct 4, 2021
    Last edited: Oct 5, 2021

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