Duet3D Logo Duet3D
    • Tags
    • Documentation
    • Order
    • Register
    • Login

    Calibrating a large delta

    Scheduled Pinned Locked Moved
    Tuning and tweaking
    5
    24
    2.8k
    Loading More Posts
    • Oldest to Newest
    • Newest to Oldest
    • Most Votes
    Reply
    • Reply as topic
    Log in to reply
    This topic has been deleted. Only users with topic management privileges can see it.
    • pabomanundefined
      paboman @dc42
      last edited by

      @dc42
      I understand, do you agree that my in probing height difference is due to tilted bed ?

      dc42undefined 1 Reply Last reply Reply Quote 0
      • dc42undefined
        dc42 administrators @paboman
        last edited by

        @paboman said in Calibrating a large delta:

        @dc42
        I understand, do you agree that my in probing height difference is due to tilted bed ?

        Not necessarily, it could also be due to the endstop adjustments being out. The trigger height of the probe arrangement in your photo should not be sensitive to effector tilt.

        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

        1 Reply Last reply Reply Quote 0
        • pabomanundefined
          paboman
          last edited by

          endstop are fixed on the top, optical type, but yes they can be triggered not at equal height

          dc42undefined 1 Reply Last reply Reply Quote 0
          • dc42undefined
            dc42 administrators @paboman
            last edited by

            @paboman said in Calibrating a large delta:

            endstop are fixed on the top, optical type, but yes they can be triggered not at equal height

            That doesn't matter, calibration will correct the offsets. The main issue with the height map that you published is that one or more of the M665 rod length, the M665 delta radius and the M92 tower steps/mm is out by a large amount.

            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

            1 Reply Last reply Reply Quote 0
            • pabomanundefined
              paboman
              last edited by

              I will be able to measure steps/mm with a dial gauge but getting the rods length is quite problematic as they are theoretically long 1155mm, I measured them with a steel ruler...but I was unable to find a caliper that big

              Do you think changing the calibration factor to 7 can get the rod length correct ?

              1 Reply Last reply Reply Quote 0
              • pabomanundefined
                paboman
                last edited by

                I have corrected the R Radius manually to get the nozzle at the same height from the bed in the center as on the circumference of the printable area, then I run the Mesh Grid and get better result then my previous:

                0_1527179534493_cal-results.jpg

                Why the probed mesh is lower than the reference plane ?

                Now I will measure if steps/mm are dialed in precisely

                thanks again

                1 Reply Last reply Reply Quote 0
                • dc42undefined
                  dc42 administrators
                  last edited by

                  That looks a lot better!

                  The probed mesh may be lower than the reference plane if your H parameter is not correct in the M665 command, or if you home the printer when mesh bed compensation is already applied (this is fixed in firmware 2.0RC5).

                  You should run delta calibration and mesh bed compensation at the same bed and hot end temperatures, in case thermal expansion has an effect.

                  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

                  pabomanundefined 1 Reply Last reply Reply Quote 0
                  • BenDieselundefined
                    BenDiesel
                    last edited by

                    If like to see bigger pic of the whole thing

                    1 Reply Last reply Reply Quote 0
                    • pabomanundefined
                      paboman @dc42
                      last edited by

                      @dc42

                      I have upgraded to the last RC5
                      Corrected my 640 step/mm as I was getting a real Z travel shorter by 3%
                      Done the automatic delta calibration and copied the values in the config.g, then run the Grid Mesh and now I am getting this mesh....something is wrong i will try to calibrate the radius by hand because before the result was more comfortable.
                      what do you think?

                      0_1527187708245_cal-results.jpg

                      1 Reply Last reply Reply Quote 0
                      • dc42undefined
                        dc42 administrators
                        last edited by

                        Are you sure that you have the correct rod length, measured between bearing centres, in the M665 L parameter?

                        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

                        pabomanundefined 1 Reply Last reply Reply Quote 0
                        • pabomanundefined
                          paboman @dc42
                          last edited by

                          @dc42 I am pretty sure is right within half a millimeter
                          I am using magnetic rods articulated on 10mm steel spheres.

                          From one end of the sphere to the other end of the sphere is 1155mm - 10mm = 1145 (I am subtracting 5mm from each sphere as the centre of rotation is given by the radius of the 10mm sphere which is 5)

                          I am getting better result, or maybe its just an illusion, with the Radius manually adjusted instead of using the R values proposed by the automatic probing, why ?

                          0_1527192206703_cal-results.jpg

                          Danalundefined 1 Reply Last reply Reply Quote 0
                          • dc42undefined
                            dc42 administrators
                            last edited by

                            Automatic calibration minimises the sums of the squares of the height errors. So for good results the probe points should cover all areas of the bed. How many probe points did you use, and how were they distributed?

                            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

                            1 Reply Last reply Reply Quote 0
                            • pabomanundefined
                              paboman
                              last edited by

                              the probing points are generated by the wizard using radius 500mm as input (for 1000mm printable area)

                              0_1527193755489_probe-points.jpg

                              1 Reply Last reply Reply Quote 0
                              • Danalundefined
                                Danal @paboman
                                last edited by

                                @paboman said in Calibrating a large delta:

                                I am using magnetic rods articulated on 10mm steel spheres.

                                From one end of the sphere to the other end of the sphere is 1155mm - 10mm = 1145 (I am subtracting 5mm from each sphere as the centre of rotation is given by the radius of the 10mm sphere which is 5)

                                1145 sounds correct if YOU MEASURED 1155 to the "outer" part of the spheres.

                                If you obtained a measurement from the manufacturer of your rods, they are NORMALLY labeled "joint center to joint center" and the subtraction would be incorrect.

                                Delta / Kossel printer fanatic

                                pabomanundefined 1 Reply Last reply Reply Quote 0
                                • pabomanundefined
                                  paboman @Danal
                                  last edited by

                                  @danal they are manufactured by myself and yes 1155 mm is the distance between the outer part of the spheres 🙂

                                  Danalundefined 1 Reply Last reply Reply Quote 0
                                  • Danalundefined
                                    Danal @paboman
                                    last edited by

                                    @paboman said in Calibrating a large delta:

                                    @danal they are manufactured by myself and yes 1155 mm is the distance between the outer part of the spheres 🙂

                                    Excellent!!

                                    When it is convenient, it would be really cool to see some pictures. There's a few pics of my 600 Dia x 600 Z Delta if you scroll down on this blog:

                                    http://danalspub.com/

                                    Delta / Kossel printer fanatic

                                    1 Reply Last reply Reply Quote 0
                                    • pabomanundefined
                                      paboman
                                      last edited by paboman

                                      @dc42 To use the saved mesh grid I understand that I need to add G92 S1 in the config.g, is that right ?

                                      dc42undefined 1 Reply Last reply Reply Quote 0
                                      • dc42undefined
                                        dc42 administrators @paboman
                                        last edited by

                                        @paboman said in Calibrating a large delta:

                                        @dc42 To use the saved mesh grid I understand that I need to add G92 S1 in the config.g, is that right ?

                                        It's better to include it at the end of your homeall.g file, or in your slicer start GCode.

                                        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

                                        pabomanundefined 1 Reply Last reply Reply Quote 0
                                        • pabomanundefined
                                          paboman @dc42
                                          last edited by paboman

                                          @dc42

                                          do you mean Homedelta.g ?

                                          I am not sure the height map is loaded properly as I still get the nozzle too high where the heightmap is showing more distance.

                                          Config.g

                                          ; Z-Probe
                                          M558 P5 H10 F600 T6000 I1                                               ; Set Z probe type to switch and the dive height + speeds (was P5)
                                          G31 P600 X0 Y0 Z12.20                                                   ; Set Z probe trigger value, offset and trigger height
                                          M557 R500 S50                                                           ; Define mesh grid R= probe Radius S= Mesh Spacing
                                          

                                          Homedelta.g

                                          ; homedelta.g
                                          ; called to home all towers on a delta printer
                                          ;
                                          ; generated by RepRapFirmware Configuration Tool on Sun Feb 25 2018 16:19:34 GMT+0100 (ora solare Europa occidentale)
                                          G91                        ; relative positioning
                                          G1 S1 X2500 Y2500 Z2500 F6000 ; move all towers to the high end stopping at the endstops (first pass)
                                          G1 X-5 Y-5 Z-5 F1800 S2    ; go down a few mm
                                          G1 S1 X10 Y10 Z10 F360     ; move all towers up once more (second pass)
                                          G1 Z-5 F1000               ; move down a few mm so that the nozzle can be centred
                                          G90                        ; absolute positioning
                                          G1 X0 Y0 F1000             ; move X+Y to the centre
                                          
                                          G92 S1			; Load Heightmap
                                          

                                          Bed.g

                                          ; bed.g
                                          ; called to perform automatic delta calibration via G32
                                          
                                          M561 ; clear any bed transform
                                          
                                          ; bed.g file for RepRapFirmware, generated by Escher3D calculator
                                          ; 16 points, 6 factors, probing radius: 500, probe offset (0, 0)
                                          ;The value of each H parameter should be (probe trigger height at that XY position) - (probe trigger height at centre of bed).
                                          
                                          G28
                                          G30 P0 X0.00 Y500.00 Z-99999 H0
                                          G30 P1 X321.39 Y383.02 Z-99999 H0
                                          G30 P2 X492.40 Y86.82 Z-99999 H0
                                          G30 P3 X433.01 Y-250.00 Z-99999 H0
                                          G30 P4 X171.01 Y-469.85 Z-99999 H0
                                          G30 P5 X-171.01 Y-469.85 Z-99999 H0
                                          G30 P6 X-433.01 Y-250.00 Z-99999 H0
                                          G30 P7 X-492.40 Y86.82 Z-99999 H0
                                          G30 P8 X-321.39 Y383.02 Z-99999 H0
                                          G30 P9 X0.00 Y250.00 Z-99999 H0
                                          G30 P10 X216.51 Y125.00 Z-99999 H0
                                          G30 P11 X216.51 Y-125.00 Z-99999 H0
                                          G30 P12 X0.00 Y-250.00 Z-99999 H0
                                          G30 P13 X-216.51 Y-125.00 Z-99999 H0
                                          G30 P14 X-216.51 Y125.00 Z-99999 H0
                                          G30 P15 X0 Y0 Z-99999 S6
                                          
                                          
                                          1 Reply Last reply Reply Quote 0
                                          • dc42undefined
                                            dc42 administrators
                                            last edited by

                                            Yes, for a delta you would put it in homedelta.g, or possibly at the end of bed.g instead if you normally auto calibrate before printing.

                                            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

                                            pabomanundefined 1 Reply Last reply Reply Quote 0
                                            • First post
                                              Last post
                                            Unless otherwise noted, all forum content is licensed under CC-BY-SA