nozzle too close to bed cr-6 SE



  • Im having an issue with the nozzle being too close to the bed after auto leveling, its at max offset 0.5, but still cant get a paper under the nozzle, the gantry is level, but its just too close, so how do I get more z offset?



  • @shinmai during auto leveling the hotend does not flex at all, just gently taps the glass, but you can see it flex a bit if I set the offset to 0, sadly I dont have a multimeter or a strain gauge



  • at 0mm the hotend will flex up a bit from pressing so hard against the glass

    This should not happen, at 0mm the hotend should just rest at the surface of the glass, basically. During auto-leveling, does the nozzle do the same thing, pressing against the glass for more than just a quick touch and flexing the hotend? I've got it tuned to just do the lightest touch on it twice and move to the next spot, and while that's maybe a bit overkill, it should definitely just tap the glass, not actually press against it hard.

    If you have a multimeter, you can check what the trimpot in the hotend assembly for the strain gauge threshold reads, and try to tweak it (VERY small amounts) to get it to trigger easier.

    If the sensitivity is so low, that the distance to the bed with the same offset at the same location is inconsistent, that would obviously explain the issues you're having.



  • @shinmai sometimes its pressing against the plate with 0.5mm offset, other times it does not, when its not to close, the prints are perfect, so its just the offset Im having problems with, and yeah, at 0mm the hotend will flex up a bit from pressing so hard against the glass, but other then that, its movement is really nice and smooth, without wobble, thats the thing I dont really get, why its doing this weird offset thing, unless is some sort of firmware bug, tried removing the glassplate, and replaced it with the one from my ender 5, exactly the same issue, so its not the glassplate atleast, did the leveling about 10 times now, the 10th time I could just get the paper under the nozzle at 0.5 offset, and the print is perfect, but I should not have to level and relevel over and over just to get it at the correct offset:/



  • So at 0mm the nozzle just touches the bed (and isn't like hard pressing against it, flexing the hotend assembly up or anything), and it moves the nozzle up every time you increment the Z-offset, right?
    So if the physical movement doesn't match the offset, clearly there's something wrong with your Z-axis movement. But if I understood correctly, you said it prints fine other than the weird z-offset. If you just move up on the Z-axis, does the X-gantry move smoothly and quietly as expected?

    Thing is, you can probably hack the extra offset in somehow (manually editing EEPROM, etc., if nothing else, just patching Marlin to add some arbritary value in), but that won't address the issue of why the nozzle isn't 0.2mm away from the bed when the offset is at 0.2mm, which is weird given how the leveling on the printer works.



  • did a test now, at max offset 0.5, I cant get a a4 paper under the nozzle, so I raised z axis with 0.1 mm until I could, had to raise it 0.2mm to get it where it should be, problem is, how to get that extra 0.2 mm z offset?



  • @shinmai hi, so far I have done about 20 prints on it, no problem at all, but today, I cant get a paper under it at max offset, I normaly use a standard paper first, then a blade to get it perfect on my other printers, that I level manually, but just a standard a4 paper have been working great on the cr6 se so far, hotend is mounted rightm not loose or low, gantry is level, bed is level, no slack anywere, thats why I dont get why its too close now at max offset, sadly I did the firmware update following crealitys guide, and now Im stuck at the boot loading screen:/



  • Just from the way ABL works on the printer, the Z-offset setting should map basically 1:1 to the actual distance from nozzle to bed, so unless you're using some corrugated card-board for paper-testing, either something is physically wrong or there's an error in the ABL related settings.

    Is your hotend mounted right, or is it loose/too low? Alternatively, is there slack in your bed? If it has some movbement and tilts when pressed, and your strain gague threshold is high-ish, ABL could conceivably measure the bed to be way lower than it's actually mounted.
    When you auto-level, the nozzle just lightly touches the surface twice, as expected, right? I've seen some videos people's CR-6 absolutely ramming the nozzle into the glass and them thinking nothing of it 😅

    A factory-reset couldn't hurt, either, I guess.


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