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    Another Bed Leveling Weirdness

    Scheduled Pinned Locked Moved
    Tuning and tweaking
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    • Phaedruxundefined
      Phaedrux Moderator
      last edited by

      I think it may be due to the magnets. Can you try placing something like a thick book on the bed at that corner and probing it to see if the resulting map is now flat or if it still has a weird spike and dip. The book would add distance between the probe and the underlying magnets.

      Z-Bot CoreXY Build | Thingiverse Profile

      remopiniundefined 1 Reply Last reply Reply Quote 0
      • remopiniundefined
        remopini @Phaedrux
        last edited by remopini

        @phaedrux Hm... that actually seems to have had a big influence... the level is obviously horrible (books aren't really flat), but there are no outliers.

        Now, the only question is: how do I make the probe less prone to fubar from the magnetic bed? I can't be the only one having issues?

        Twigzundefined 1 Reply Last reply Reply Quote 0
        • Twigzundefined
          Twigz @remopini
          last edited by

          @remopini as stated in the second post, you can set a different spacing (more or less points) for your mesh and avoid the spot all together. This will probably be a bit of trail and error.

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          • Phaedruxundefined
            Phaedrux Moderator
            last edited by

            As @Twigz says, you'll have to jiggle your grid around. You;re not the only one encountering this. It's a side effect of the current popularity of magnetic bed surfaces.

            What version of BLTouch are you using? Does it have the metal, or plastic pin?

            What BLTouch mount are you using? Can you put it in a different location?

            Z-Bot CoreXY Build | Thingiverse Profile

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            • remopiniundefined
              remopini
              last edited by

              @Twigz @Phaedrux I got a 2.0 (platic pin). The mount is one of those Titan Aero all-in-one mounts, so can't really change the position (I'd have to design my own mount for that). But I can of course change the mesh (or shift it around by some factor). I'll do some trial and error tomorrow to figure out, whether I can find a setup that works. Will update here with any findings.

              Twigzundefined 1 Reply Last reply Reply Quote 0
              • Phaedruxundefined
                Phaedrux Moderator
                last edited by

                I'll be in a similar situation soon with the Ender 3 and BLTouch. So i'm interested in seeing what you find.

                Z-Bot CoreXY Build | Thingiverse Profile

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                • Twigzundefined
                  Twigz @remopini
                  last edited by

                  @remopini you can also try to turn the bltouch 180 degrees. I had mine too close to the hotend and it acted up. Turning it around meant the board was further away from the hotend and it worked flawless.
                  Maybe the all metal aero has some influence?

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                  • remopiniundefined
                    remopini
                    last edited by

                    @Twigz The PCB is already turned the "right way", i.e as far away from the hotend as it can (with the mount I have):
                    0_1557178723213_20190506_233733.jpg

                    Electrically or magnetically, I can't imagine the hotend influencing the BLTouch too much in that setup (the closest active component is more than 40mm from the BLTouch).

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                    • remopiniundefined
                      remopini
                      last edited by

                      Ok, twiddled a little bit with the mesh definition. Moving everything over a few mm did the trick with the one outlier:
                      0_1557211516059_bed level 03.png

                      However, the systematic measurement error (that back left corner is NOT 0.48 higher than the other corners) persists.

                      With mesh compensation enabled, the nozzle is now basically half a mm higher up in that corner than in all others. So, for whatever reason, there is still a significant measurement error introduced in that corner.

                      Current ideas:

                      • Since that is the corner where all the cables are, could it be interference? But the very regular error kind of suggests otherwise (interference wouldn't usually be regular)
                      • Some mechanical problem that only manifests during probing, but not during normal moves. Also not super likely.
                      • The bed magnetism is influencing the measurement. Possible, but nothing I could do anything against, so I'd be limited to use the BLTouch for the initial probe in the front and not do any mesh compensation.
                      • Something other I can't think of right now...
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                      • Vetiundefined
                        Veti
                        last edited by

                        you could try building this.
                        https://www.thingiverse.com/thing:3303618

                        due to the optical sensor it is less prone to interference.

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                        • remopiniundefined
                          remopini
                          last edited by

                          @Veti I kind of want to try to get the $50 thing to work first before giving up and going with something completely different. BTW: I wouldn't go with an opto-switch solution, they are rather imprecise.

                          As a last resort, I can always try to shield the BLTouch somehow, but finding thin ferromagnetic foil is probably difficult.

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                          • Vetiundefined
                            Veti
                            last edited by

                            @remopini said in Another Bed Leveling Weirdness:

                            I wouldn't go with an opto-switch solution, they are rather imprecise.

                            i get a standard deviation of 0.002. I would not call that imprecise.

                            remopiniundefined 1 Reply Last reply Reply Quote 0
                            • remopiniundefined
                              remopini @Veti
                              last edited by

                              @veti Not based on my experience, but it's great if you get that kind of performance out of it 🙂

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