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    Offset understanding

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    • Phaedruxundefined
      Phaedrux Moderator
      last edited by

      If you do that test several times is the result consistently -0.14?

      G31 is the probe offset in XYZ

      Z-Bot CoreXY Build | Thingiverse Profile

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      • hevilpundefined
        hevilp
        last edited by

        You would help me more if you explain what the offset really mean, what it does. I read it in the wiki, but I dont understand.

        Is my question so unclear?

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        • Phaedruxundefined
          Phaedrux Moderator
          last edited by

          G31 tells the system where the probe is in relation to the nozzle tip.
          So in your case the nozzle tip is the probe so x and y are 0. But because the nozzle tip presses into the bed slightly before the probe registers the z value is -0.14. meaning the probe is slightly below the surface of the bed when it triggers.

          Z-Bot CoreXY Build | Thingiverse Profile

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          • hevilpundefined
            hevilp
            last edited by hevilp

            That brings me to 2 questions:

            1. My sensetive is so high, when I watch while G30, the nozzle tips just a very little bit the bed.
            2. Is my offset is right, the should be no gap between nozzle and bed?, right?

            I did it now 3 times in a row in the center of the bed:

            -0,04 and -0,04 and 0,013.

            Why does it differs so much from my first value -0,14, which was in one corner of the bed?

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            • Phaedruxundefined
              Phaedrux Moderator
              last edited by

              I'm not very familiar with tuning the precision piezo, but I suggest you follow the documentation as closely as possible.

              To get a good average value for G31 Z you should measure it with G30 S-1 ten times and take the average. Center of the bed would be the best place to probe. It would also be a good ideal to try and mechanically level your bed as good as you can first. It would also help to use a hot nozzle and hot bed.

              Z-Bot CoreXY Build | Thingiverse Profile

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              • hevilpundefined
                hevilp
                last edited by

                My piezo doesn't work reliable in some way.

                I will open another thread for it, it is annoying....

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                • hevilpundefined
                  hevilp
                  last edited by

                  How do you do the Z-offset calibration?

                  With a piece of paper between nozzle and bed or nozzle and bed direct in contact.

                  My thought is, to have the nozzle really have on the bed with Z0 and then put the needed (normally paper) gap in the G92 command to have it perfect.

                  Which is the best way?

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                  • Phaedruxundefined
                    Phaedrux Moderator
                    last edited by

                    I touch the nozzle to the bed and don't use paper at all. I don't use a G92 either. That's really what a z probe gains for you. You don't have to fiddle with paper or other tricks anymore.

                    Z0 is touching the bed and the first layer height is exactly what the slicer asks for.

                    Z-Bot CoreXY Build | Thingiverse Profile

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                    • hevilpundefined
                      hevilp
                      last edited by

                      I got a JGAuroa A5 (no autobed level, prusa design) beside my HEVO (piezo).

                      On the A5 I do a mechanical bed level with 0,15mm metall sheet under the nozzle between the bed. Exactly shown here https://www.youtube.com/watch?v=7G2OftpUxow&t=32s

                      If I bring the nozzle to the bed with no gap, no filament comes out.

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                      • Phaedruxundefined
                        Phaedrux Moderator @hevilp
                        last edited by

                        @hevilp the gap should be from your first layer height, no?

                        Z-Bot CoreXY Build | Thingiverse Profile

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                        • hevilpundefined
                          hevilp
                          last edited by hevilp

                          Yep,

                          If I level my bed with the 0,15 mm metall sheet, my first nozzle height, if I print 0,2mm should be 0,35mm or?
                          0,15mm is the distance I gave with the metall sheet, where the printer thinks it is Z0
                          and
                          0,2mm for the layer height.
                          It is working fine. In the link is the code of the lcd where the leveling is coded.

                          I wonder where the gap of 0,15mm would be with my HEVO?

                          https://www.dropbox.com/s/ccreium22rki3cq/JGAurora A5 Custom LCD firmware - 20180111.zip?dl=0&file_subpath=%2FJGAurora+A5+Custom+LCD+firmware+-+20180111%2Fmks_config.txt

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