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    Core XY movement issues

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    Duet Hardware and wiring
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    • deckingmanundefined
      deckingman
      last edited by

      Try this. Do a longish move in X, say 100 mm and measure the Y distance and direction. Then swap the A and B motors (the ones that do X and Y). Repeat the X move. If the movement in Y changes direction, then it's an issue with the motor. At least that will eliminate one variable.

      Ian
      https://somei3deas.wordpress.com/
      https://www.youtube.com/@deckingman

      FxxTooundefined 2 Replies Last reply Reply Quote 0
      • FxxTooundefined
        FxxToo @deckingman
        last edited by FxxToo

        @deckingman
        Excellent I will try that. I was just starting to pull the Duet board out. Wiil try that right after lunch. and Post the results.
        Do you mean remap the motors or physically swap the motors?
        Thanks!
        RJ

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

          @fxxtoo I would think to physically swap them.

          Z-Bot CoreXY Build | Thingiverse Profile

          FxxTooundefined 1 Reply Last reply Reply Quote 0
          • FxxTooundefined
            FxxToo @Phaedrux
            last edited by

            @phaedrux
            Thanks. I just did that. Same thing. ARRGG!
            RJ

            Phaedruxundefined mrehorstdmdundefined 2 Replies Last reply Reply Quote 0
            • Phaedruxundefined
              Phaedrux Moderator @FxxToo
              last edited by

              @fxxtoo at least you know it doesn't follow the motor, so the motors are ok.

              Z-Bot CoreXY Build | Thingiverse Profile

              FxxTooundefined 1 Reply Last reply Reply Quote 0
              • FxxTooundefined
                FxxToo @deckingman
                last edited by

                @deckingman
                just finished swapping the steppers. I left the M92 the same. Before I swapped the motors, I did a G1 x250, the head did not move in the Y. I just did a I did a G1 x250 and Y did not move. So the same as before.
                RJ

                deckingmanundefined 1 Reply Last reply Reply Quote 0
                • FxxTooundefined
                  FxxToo @Phaedrux
                  last edited by

                  @phaedrux
                  Thanks. At least that is some progress.
                  RJ

                  JoergS5undefined 2 Replies Last reply Reply Quote 0
                  • JoergS5undefined
                    JoergS5 @FxxToo
                    last edited by

                    @fxxtoo

                    I looked at
                    https://forum.duet3d.com/topic/4958/y-axis-moves-when-only-x-is-commanded/10
                    again, where you made some pictures of your printer.

                    I wondered whether the linear X guide is connected stable enough (I mean the linear guide in the middle, connected to hotend). I had a problem at my own CoreXY printer that moving by hand was ok on one side, but not at the other. It blocked totally because the connection bends a bit and the one linear guide blocks.

                    In your picture the one side is connected by a screw, on the other by a linear mgn guide which is very good to level temperature effects. But the disctance between linear guide and aluminium cage seems to be different at both sides and the linear guide alone seems to be too little support (one or two screws on one side). The difference at the mgn side seems to be less than the other side. On the mgn side the belts are not in the middle in respect to the cage.

                    The difference leads to different Y positions at the both sides and leads to become stuck because the pulleys have different positions.

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                    • JoergS5undefined
                      JoergS5 @FxxToo
                      last edited by

                      @fxxtoo

                      At this side

                      0_1531806870382_detail.jpg

                      the left belt side is very strange. It seems to go around a shaft and so a nonlinear movement is introduced.

                      FxxTooundefined 1 Reply Last reply Reply Quote 0
                      • mrehorstdmdundefined
                        mrehorstdmd @FxxToo
                        last edited by

                        @fxxtoo I don't think it has anything to do with your printer's problem, but what @JoergS5 is pointing out is that the X axis bearing block at the P2 pulley assembly appears to be thicker than the spacer at the end of the X axis rail at the P1 pulley assembly. When I built my printer, I made the spacer to match the thickness of the bearing block. That keeps the P1 and P2 pulleys at exactly the same Y position when the rails are square.

                        It shouldn't make any difference as long as you ensure that the X and Y guide rails are square when you tension the belts. In other words, don't use the pulley position along Y to determine if it's square, use the guide rails as the reference.

                        @JoergS5 The left side belt comes off the pulley in the block and goes directly to the extruder carriage. You're seeing parallax - there's no shaft- the top of the pulley assembly has 4 tool access holes for screwing the assembly to the Y axis bearing block..

                        https://drmrehorst.blogspot.com/

                        JoergS5undefined FxxTooundefined 2 Replies Last reply Reply Quote 0
                        • deckingmanundefined
                          deckingman @FxxToo
                          last edited by

                          @fxxtoo said in Core XY movement issues:

                          @deckingman
                          just finished swapping the steppers. I left the M92 the same. Before I swapped the motors, I did a G1 x250, the head did not move in the Y. I just did a I did a G1 x250 and Y did not move. So the same as before.
                          RJ

                          What? I thought you were saying that when you moved in X, there was movement in Y as well. Now you are saying there isn't. Totally confused now by what the problem actually is.

                          Ian
                          https://somei3deas.wordpress.com/
                          https://www.youtube.com/@deckingman

                          FxxTooundefined 1 Reply Last reply Reply Quote 0
                          • JoergS5undefined
                            JoergS5 @mrehorstdmd
                            last edited by

                            @mrehorstdmd Thank you for explaining the holes. It's difficult to analyze from a photo.

                            The reason for this all is still mysterious, we should place bets. I heard the British like to bet.

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                            • FxxTooundefined
                              FxxToo @deckingman
                              last edited by

                              @deckingman I changed the settings in the M92 from X320 Y319 and the movement stopped and appears to be working normally. I did this based upon the 2nd link I posted as that was a similar problem as mine.
                              I left the M92 setting the same,adjusted so there was no movement in the Y when X was moved. I still have it set up with the motors swapped. I can set the M92 back to x320 y320 and try it both ways. I was going to take the board out of the enclosure to really examine the boardto see what I find. After some of the post I have found about board issues and pictures I have found, missing or bad solder joints, etc.

                              pro3dundefined deckingmanundefined 2 Replies Last reply Reply Quote 0
                              • pro3dundefined
                                pro3d @FxxToo
                                last edited by

                                @fxxtoo
                                I am looking at the belt alignment. Are they the same on both sides? Optimal would be to run them inline and not in an angle like you do as this might influence the movement if not mirrored perfectly. Or am I watching something the wrong way

                                Valkyrie DIY High Temp 3D Printer

                                R&D - Engineering Designer - Viking 3D Printers
                                https://vkingprinter.com/

                                FxxTooundefined 1 Reply Last reply Reply Quote 0
                                • FxxTooundefined
                                  FxxToo @JoergS5
                                  last edited by

                                  @joergs5 I thought I made the distance from the pulley blocks on the Y axis to the rail on the X axis were the same on both sides. I will check that when I get off work. Thanks for bringing that up!
                                  rj

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                                  • deckingmanundefined
                                    deckingman @FxxToo
                                    last edited by

                                    @fxxtoo Ah I see. Sorry I forgot that you had set the X and Y steps per mm differently as a work around. I guess I kind of assumed that you would use the same steps per mm on both X and Y for the purpose of that test. No matter. The fact that you get the same movement with the motors physically swapped at least eliminates the motors as a cause of the problem.

                                    Ian
                                    https://somei3deas.wordpress.com/
                                    https://www.youtube.com/@deckingman

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                                    • FxxTooundefined
                                      FxxToo @pro3d
                                      last edited by

                                      @pro3d
                                      I think you are talking about the belt that goes around the motor pulley and back around to the extruder mount.
                                      This is the way I did them.
                                      0_1531842752017_top simple_belts_corexy_annotated.jpg

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                                      • T3P3Tonyundefined
                                        T3P3Tony administrators
                                        last edited by

                                        Can you confirm that you have physically swapped the motor connectors between A and B motors. If so what happened with the issue?

                                        www.duet3d.com

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                                        • FxxTooundefined
                                          FxxToo @T3P3Tony
                                          last edited by FxxToo

                                          @t3p3tony
                                          Hi Tony, Thanks for posting. I would like to be sure about what you are asking me to do.
                                          At this time I have done the testing as per the docs.
                                          G91 G1 S2 X100 F3000 ; MOVES X+ AND Y+ , as it should
                                          G91 G1 S2 Y100 F3000 ; MOVES X+ AND Y- .
                                          Doing a G90 G1 X100 causes Y to move about 3 mm in the + dir
                                          Doing a G90 G1 Y100 causes X to move about 3 mm in the + dir
                                          After changing * and still at M92 X320 Y319 doing the above,
                                          the X only moves when the same command is sent, same as when the Y command is sent.
                                          I have physically swapped the A and B motors, And with the M92 X320 Y319, it behaves normally. With M92 320 Y320, it reverts to Y moving a bit when moving X and vice versa. But the new A motor went to the A connector. So that is where my question comes in.
                                          I can tell you what it will do, with the connectors in the correct places, a G90 G1 X100 command will cause X to move 100 to the plus and the Y to move ~3mm to the plus. The same with a G1 Y100.
                                          If I swap the connectors and run it twon't that change the directions of the motors? Will I have to change those settings as well?
                                          Should I set the steps back to M92 X320 Y320 first? Then run G1 X100 and then G1 Y100. Then swap the connectors on the board and then run the same commands, to see what it does before and after? Sorry if I seem a bit flustered, as I am.
                                          RJ

                                          deckingmanundefined 1 Reply Last reply Reply Quote 0
                                          • deckingmanundefined
                                            deckingman @FxxToo
                                            last edited by deckingman

                                            @fxxtoo I think what you'll need to do to accomplish what Tony is asking is to swap the motor connectors, then re-map the drives. So you'll need to add this to the start of your drive section in config.g

                                            M584 X1 Y0

                                            Make sure you put it at the start of the drive section. Your motor directions are all the same so they should not be affected.

                                            So you'll physically swap the stepper connectors on the board so that what was X is now connected to Y and what was Y is now connected to X. Then by adding that line, it'll swap the drivers so you should end up with exactly the same movement. If you get a different result, then it would indicate a faulty driver.

                                            So to be sure, set the steps per mm the same for both axes. Do the long x move first and note any Y movement, then swap the cables and re-map the drives, then repeat.

                                            Ian
                                            https://somei3deas.wordpress.com/
                                            https://www.youtube.com/@deckingman

                                            FxxTooundefined 1 Reply Last reply Reply Quote 0
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