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    inconsistent Z movement

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    • Phaedruxundefined
      Phaedrux Moderator
      last edited by

      Are you using those new motors on the Z axis as well?

      Is this a new problem after those recent changes?

      You can try bumping the motor current on the Z axis a bit. Try 1300ma.

      How heavy is the gantry?

      Have you squared up the gantry so that it's even on both sides? If you have a spare driver you could put each Z motor on it's own driver. (just add the second driver number to the M584 Z mapping, nothing else needs to change)

      Z-Bot CoreXY Build | Thingiverse Profile

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      • kmartundefined
        kmart @Phaedrux
        last edited by

        @Phaedrux said in inconsistent Z movement:

        Are you using those new motors on the Z axis as well?

        Is this a new problem after those recent changes?

        You can try bumping the motor current on the Z axis a bit. Try 1300ma.

        How heavy is the gantry?

        Have you squared up the gantry so that it's even on both sides? If you have a spare driver you could put each Z motor on it's own driver. (just add the second driver number to the M584 Z mapping, nothing else needs to change)

        Thanks for your reply.

        Yes i used those motors on the Z and this is only a problem after my changes. Prior to this everything was working reliably, i didn't have failed prints.

        I will play with the motor current and see if that makes any difference.
        I never weighed the gantry, previously it was a printed carriage with E3D hot end (bowden) on 2 smooth rods.

        After the change it's a piece of 2020 extrusion w/ linear rail, still printed carriage but direct drive. So it's definitely heavier... Just not sure how heavy.

        Everything is square, i guess the last attempt will be to run each motor on its own stepper. But i did run the same configuration prior to the changes so I don't know if that's really the problem or not... But I'm not an expert.

        Thanks again

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        • kmartundefined
          kmart
          last edited by

          No progress really. I bumped up the current as much as i could while keeping the motors from getting hot (1375mA) but i still get the inconsistent Z movement.

          Next step will be to try independent steppers for each Z motor. Time is limited to work on this but hopefully i can try and get that setup in the next 1-2 days

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          • kmartundefined
            kmart @Phaedrux
            last edited by

            @Phaedrux said in inconsistent Z movement:

            M584

            So i setup this up

            M584 X0 Y1 Z2:4 E3
            

            But now i get this

            G28
            Warning: motor phase A may be disconnected reported by driver(s) 2 4
            Warning: motor phase B may be disconnected reported by driver(s) 2 4
            

            Is this because now one motor from Z is disconnected? How do i fix that?

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            • Phaedruxundefined
              Phaedrux Moderator
              last edited by

              What is connected to drivers 2 and 4?
              Do you have the jumpers installed in the second Z port?

              Z-Bot CoreXY Build | Thingiverse Profile

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              • kmartundefined
                kmart @Phaedrux
                last edited by kmart

                @Phaedrux said in inconsistent Z movement:

                What is connected to drivers 2 and 4?

                Originally Each Z motor was connected to Z1/Z2 (driver 2), i moved one to E1 (Driver 4) for each to be on their own driver as you suggested

                @Phaedrux said in inconsistent Z movement:

                Do you have the jumpers installed in the second Z port?

                I didn't realize in the wiring diagram that there was option A and option B. After seeing that i installed the jumpers and now both motors are moving.

                So now new issue. Home x and Home Y lift Z by a few mm. I can see one Z motor is spinning faster than the other because one coupler expands... I doubt this is config related, what could potentially cause this, bad wiring?

                Edit, I just realized they're spinning in opposite directions
                Edit 2: Fixed that with M569 for driver 4. Will continue to test

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                • Phaedruxundefined
                  Phaedrux Moderator
                  last edited by

                  ; Drives
                  M569 P0 S1 ; X goes forwards
                  M569 P1 S1 ; Y goes forwards
                  M569 P2 S0 ; Z goes backwards
                  M569 P3 S0 ; E0 goes backwards

                  Add driver 4 to the list and set the direction

                  Z-Bot CoreXY Build | Thingiverse Profile

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                  • kmartundefined
                    kmart @Phaedrux
                    last edited by

                    @Phaedrux

                    Yeah i had caught that just after posting. Fixed it and all is good.

                    Preliminary testing using a feeler gauge is that the height movement is consistent, or at least more than it was before.

                    But I've been wondering. Prior to all my changes i ran 12V, with the original Anet A8 stepper motors, with the dual Z connected to Z1 and Z2 and never had this problem.

                    Is there something wrong with the new motors i bought? Should i be looking at just replacing the Z motors with something more suitable?

                    Thanks,

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                    • dc42undefined
                      dc42 administrators
                      last edited by

                      The specifications of those motors look OK to me. Check that they move freely.

                      Duet WiFi hardware designer and firmware engineer
                      Please do not ask me for Duet support via PM or email, use the forum
                      http://www.escher3d.com, https://miscsolutions.wordpress.com

                      kmartundefined 1 Reply Last reply Reply Quote 0
                      • kmartundefined
                        kmart @dc42
                        last edited by

                        @dc42

                        As far as I can tell they do, and I've quadruple checked the linear rail alignment that the gantry moves freely up and down without binding.

                        The only other thing i can think of is that i also added anti-backlash lead screw nuts... They were generic off of amazon, maybe they're causing some kind of additional resistance.

                        I may end up disassembling/reassembling the whole thing and verifying all wiring as well because this is the first time I've been really stumped.

                        But after a few tests this morning the consistency seems more reliable with independent Z drives so I'm going to move onto the next problem.

                        Thanks,

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

                          @kmart said in inconsistent Z movement:

                          maybe they're causing some kind of additional resistance.

                          That's typically what they do. Sometimes to the point of binding if the motor isn't powerful enough. Backlash is typically not a problem on Z. So I'd try removing them.

                          Z-Bot CoreXY Build | Thingiverse Profile

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