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    Controlled arc problem

    Scheduled Pinned Locked Moved Solved
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    • neiloundefined
      neilo
      last edited by

      @dc42 Hi there I'm using RRF 3.1.1. Is it worth giving the latest version a go? (3.2)

      @alankilian I'll try some other moves in the meantime today 🙂

      Cheers

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      • dc42undefined
        dc42 administrators
        last edited by

        Yes, please try firmware 3.2RC2.

        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

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        • neiloundefined
          neilo
          last edited by

          @dc42 sorry it's not clear to me whether I can go direct from 3.1.1 to 3.2 RC2? The RC2 release notes say the iap files have not changed since RC1 but cannot see them in the RC1 area to copy across.

          Also RC1 notes state: "Users of Duet + Single Board Computer should upgrade from the packager server as usual." Not clear to me where/what the package server is!

          Thanks,
          Neil

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          • Phaedruxundefined
            Phaedrux Moderator
            last edited by

            https://github.com/Duet3D/RepRapFirmware/releases/tag/3.2RC1

            There are 4 files with SDiap32 in their names.

            https://duet3d.dozuki.com/Wiki/Getting_Started_With_Duet_3#Section_Software_Installation

            You can find the instructions for adding the unstable branch package server here.

            Z-Bot CoreXY Build | Thingiverse Profile

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            • neiloundefined
              neilo
              last edited by

              Thanks very much for your assistance, the good news is that the firmware upload (RRF3.2RC2)went fine, the bad news is that the mis-behaviour is still present.
              For example a simple square is not completing (fig 1) WIN_20210103_19_24_45_Pro.jpg
              or a sequence of simple moves (fig 2)WIN_20210103_19_25_08_Pro.jpg .
              This time I've uploaded the config and gcode files for the above if someone could please spot the deliberate mistakeconfig.g
              arc.g
              squaretest.g

              cjmundefined 1 Reply Last reply Reply Quote 0
              • whopping pochardundefined
                whopping pochard
                last edited by

                Your 'squaretest' file has only G1 moves, right? Are you sure you aren't missing steps due to a mechanical or electrical problem?

                1 Reply Last reply Reply Quote 1
                • cjmundefined
                  cjm @neilo
                  last edited by

                  @neilo

                  I've used a Duet 2 board running RepRapFirmware for Duet 2 WiFi/Ethernet 3.2-beta1 (2020-09-15b1) with a homebrew CNC to machine a test piece containing diamond, circle and square sections:

                  SquareDiamondCircle.jpg

                  The g-code for this with a 5mm diameter end mill is as follows and contains both G2 and G3 commands that the Duet appears to have executed correctly:

                  SquareDiamondCircle 42mm.g

                  The finishing passes for the circular section are complete circles so one assumes should have shown up the same sort of error you're seeing if this was intrinsic to the Duet hardware/firmware?

                  Perhaps trying this g-code file might help diagnose the problem?

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                  • neiloundefined
                    neilo
                    last edited by

                    @whopping-pochard that's right just trying to keep it simple with G1 commands in one file. I've added another test (fig 3)fig3.jpg
                    and it appears to act erratically. Mechanically it looks fine, it's belt drive on X and Y NEMA 23 FYI .
                    steps.g

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                    • neiloundefined
                      neilo
                      last edited by

                      @cjm just seen your post - many thanks I will try it out tomorrow.

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                      • neiloundefined
                        neilo
                        last edited by

                        @cjm here is the result: Still looks weird and clearly incorrect. I used a 1/4 inch bit so slight dimensional difference but does not explain for me the strange behaviour.
                        Would you mind sharing your config.g file with me please?
                        WIN_20210106_11_07_32_Pro.jpg
                        Thanks,
                        Neil

                        droftartsundefined 1 Reply Last reply Reply Quote 0
                        • droftartsundefined
                          droftarts administrators @neilo
                          last edited by

                          @neilo I think this is a mechanically issue. My best guess is that the X pulley is slipping on the motor shaft, because the first move of any change in direction in X causes the movement error, but subsequent ones do not. Probably the grub screw on the pulley is loose, allowing a limited range of movement.

                          Ian

                          Bed-slinger - Mini5+ WiFi/1LC | RRP Fisher v1 - D2 WiFi | Polargraph - D2 WiFi | TronXY X5S - 6HC/Roto | CNC router - 6HC | Tractus3D T1250 - D2 Eth

                          1 Reply Last reply Reply Quote 2
                          • sonderzugundefined
                            sonderzug
                            last edited by

                            I second @droftarts opinion; circles with horizontal and vertical flat spots (i.e. corresponding to the direction change of the x respectively the y axis) indicate mechanical backlash, quite noticable in your case.

                            1 Reply Last reply Reply Quote 1
                            • alankilianundefined
                              alankilian
                              last edited by

                              One way to test this theory is to make a square, but rotated 90-degrees.

                              That way, you get two reversals of each axis while the other axis is moving continuously in the same direction.

                              You'll see the vertices get messed up if you've got a lot of backlash.

                              AND you can do it with just G1 moves.

                              SeemeCNC Rostock Max V3 converted to V3.2 with a Duet2 Ethernet Firmware 3.2 and SE300

                              droftartsundefined 1 Reply Last reply Reply Quote 0
                              • droftartsundefined
                                droftarts administrators @alankilian
                                last edited by

                                @alankilian said in Controlled arc problem:

                                One way to test this theory is to make a square, but rotated 90-degrees.

                                Don't you mean 45 degrees?!

                                Ian

                                Bed-slinger - Mini5+ WiFi/1LC | RRP Fisher v1 - D2 WiFi | Polargraph - D2 WiFi | TronXY X5S - 6HC/Roto | CNC router - 6HC | Tractus3D T1250 - D2 Eth

                                alankilianundefined 1 Reply Last reply Reply Quote 1
                                • neiloundefined
                                  neilo
                                  last edited by

                                  Thanks folks for the opinions really appreciate independent advice! I will focus on the mechanicals and re-test the square / diamond combo.
                                  Neil

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                                  • alankilianundefined
                                    alankilian @droftarts
                                    last edited by

                                    @droftarts said in Controlled arc problem:

                                    Don't you mean 45 degrees?!

                                    Ha ha.

                                    Yes. Thanks for catching my lack-of-coffee posting.

                                    SeemeCNC Rostock Max V3 converted to V3.2 with a Duet2 Ethernet Firmware 3.2 and SE300

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                                    • cjmundefined
                                      cjm
                                      last edited by cjm

                                      @neilo The behaviour does look odd.
                                      It is interesting that some of the part (e.g. the upper left quadrant) is machined OK over multiple layers.
                                      As mentioned by others, this implies something is loose, perhaps a drive block, so that when the axis is driven in one direction the slack is taken up and the movement is controlled, but when there is a change of direction, the slack needs to be taken up in the other direction before movement control is restored. i.e. backlash, but with much more movement (around 4-5mm by the looks of the part) than normal.
                                      With the spindle/router powered down and unplugged for safety, if you send the machine to XY coordinates in the middle of its range and then manually try move the spindle/axes carriages in X and Y directions what do you feel?
                                      Everything should be tight, with no knock or play.

                                      I'm not sure it will help but as requested here's my config.sys file:
                                      config.g

                                      1 Reply Last reply Reply Quote 1
                                      • alankilianundefined
                                        alankilian
                                        last edited by

                                        This seems like a big enough error that you should be able to measure it with a ruler.

                                        Try:

                                        g0 x0 y0
                                        (Mark the position)
                                        g0 x100
                                        (Check to see if it moved 100mm)
                                        g0 x0
                                        (Check to see if it moved 100mm back)

                                        If there's a lot of backlash in the X mechanics, you'll see one or the other of those moves be less than 100mm

                                        SeemeCNC Rostock Max V3 converted to V3.2 with a Duet2 Ethernet Firmware 3.2 and SE300

                                        1 Reply Last reply Reply Quote 0
                                        • neiloundefined
                                          neilo
                                          last edited by

                                          Dear all, thanks so much for the advice, the loose grub screw was the root cause which was definitely in my blind spot! Learnt a lot and really appreciate the support, looking much better now with some tweaks.
                                          Neil
                                          WIN_20210109_13_55_44_Pro.jpg

                                          cjmundefined 1 Reply Last reply Reply Quote 4
                                          • whopping pochardundefined
                                            whopping pochard
                                            last edited by

                                            Hooray!! Glad you solved it!

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