Delta Printer Nozzle height


  • administrators

    I think the problem is that your calibration deviation of 1.581mm is much too high. With a Smart Effector and a good build, you should easily be able to get it below 0.1mm.

    Please check the points at https://duet3d.dozuki.com/Wiki/Calibrating_a_delta_printer#Section_Make_sure_your_build_is_accurate and see if you can spot anything wrong. Also please post your bed.g file.



  • @dc42:

    I think the problem is that your calibration deviation of 1.581mm is much too high. With a Smart Effector and a good build, you should easily be able to get it below 0.1mm.

    Please check the points at https://duet3d.dozuki.com/Wiki/Calibrating_a_delta_printer#Section_Make_sure_your_build_is_accurate and see if you can spot anything wrong. Also please post your bed.g file.

    Here is the bed.g file, I will have to check my build later, just came in after clearing our 20 inches of snow off the cars and driveway and I am beat.

    ; bed.g
    ; called to perform automatic delta calibration via G32
    ;
    ; generated by RepRapFirmware Configuration Tool on Thu Mar 08 2018 15:49:43 GMT-0500 (Eastern Standard Time)
    M561 ; clear any bed transform
    G28 ; home all towers
    ; Probe the bed at 3 peripheral and 0 halfway points, and perform 3-factor auto compensation
    ; Before running this, you should have set up your Z-probe trigger height to suit your build, in the G31 command in config.g.
    G30 P0 X0 Y104.9 H0 Z-99999
    G30 P1 X90.85 Y-52.45 H0 Z-99999
    G30 P2 X-90.85 Y-52.45 H0 Z-99999
    G30 P3 X0 Y0 H0 Z-99999 S3
    ; Use S-1 for measurements only, without calculations. Use S4 for endstop heights and Z-height only. Use S6 for full 6 factors
    ; If your Z probe has significantly different trigger heights depending on XY position, adjust the H parameters in the G30 commands accordingly. The value of each H parameter should be (trigger height at that XY position) - (trigger height at centre of bed)



  • @dc42:

    @Billhc83:

    This is meant to be manually done once delta calibration is finished.

    Jog the head to the bed until it just grabs a piece of regular paper. Send g92 z0 via pronterface or DWC. Upload and print. I only do this once when I start the machine.

    It should not be necessary to set the height manually using G92, unless the Z probe is not giving consistent results.

    I agree but I find lighting at different times of the day can affect the reading slightly. It is just easier for me to eliminate the variable. Although with the baby step function small variances are easily fixed now



  • @Quadcells:

    @dc42:

    I think the problem is that your calibration deviation of 1.581mm is much too high. With a Smart Effector and a good build, you should easily be able to get it below 0.1mm.

    Please check the points at https://duet3d.dozuki.com/Wiki/Calibrating_a_delta_printer#Section_Make_sure_your_build_is_accurate and see if you can spot anything wrong. Also please post your bed.g file.

    Here is the bed.g file, I will have to check my build later, just came in after clearing our 20 inches of snow off the cars and driveway and I am beat.

    ; bed.g
    ; called to perform automatic delta calibration via G32
    ;
    ; generated by RepRapFirmware Configuration Tool on Thu Mar 08 2018 15:49:43 GMT-0500 (Eastern Standard Time)
    M561 ; clear any bed transform
    G28 ; home all towers
    ; Probe the bed at 3 peripheral and 0 halfway points, and perform 3-factor auto compensation
    ; Before running this, you should have set up your Z-probe trigger height to suit your build, in the G31 command in config.g.
    G30 P0 X0 Y104.9 H0 Z-99999
    G30 P1 X90.85 Y-52.45 H0 Z-99999
    G30 P2 X-90.85 Y-52.45 H0 Z-99999
    G30 P3 X0 Y0 H0 Z-99999 S3
    ; Use S-1 for measurements only, without calculations. Use S4 for endstop heights and Z-height only. Use S6 for full 6 factors
    ; If your Z probe has significantly different trigger heights depending on XY position, adjust the H parameters in the G30 commands accordingly. The value of each H parameter should be (trigger height at that XY position) - (trigger height at centre of bed)

    Your bed.g is probably causing your issue.

    I would recommend you go to http://www.escher3d.com/pages/wizards/wizardbed.php and generate a ned BED.G File using at least the default probe settings but change the bed size to suit your build and manually edit the last G30 line it spits out to be S8 at the end rather than S6 and try again.

    HTH Doug


  • administrators

    Yes, the problem is you are only doing 3-factor calibration, so the delta radius isn't being calibrated - and I suspect your delta radius setting is significantly in error. You should use at least S4, and normally S6 or S8.



  • Doug & David,
    That was it.
    I ran the bed.g configuration tool at http://www.escher3d.com/pages/wizards/wizardbed.php using S6 total of 16 points.
    Paste it in my bed.g file and changed G31 trigger height back to Z-0.1.
    Results for deviation now 0.088
    Re-printed my 20mm test cube and now it measures X = 20.12, Y = 20.15 , Z = 20.10.
    So close to what it should be.
    Thank you!


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