Dudes of bed compensation

  • Hi,

    I don't have clear witch method use for bed compensation….

    I have see 2 metods:

    A— Simple

    1. Setup sensor offset
    2. Write In bed.g, list of probe points
    3. Execute CALIBRATION, from web interface.

    B— Detailed

    Explained here: https://www.duet3d.com/wiki/Using_mesh_bed_compensation

    1. Define bed size and spacingof probe points. Goode M557 (suposse in bed.g)
    2. Calibrate the bed. Goode G29
    3. Probe the bed, Goode G32

    What method is correct?
    What method give accurate results?

  • B is correct.

  • ok,

    later try…. this bed.g file, can work?

    ; bed.g file for RepRapFirmware, generated by Me
    ; Radius 150mm, Spacing 20 mm
    M557 R150 S20           ; probe within a radius of 150mm from the centre with a mesh spacing of 20mm
    G29			; Calibrate the bed
    G32			; Probe the bed

  • Your bed.g should look something like this.

    ; Auto calibration routine for delta printers
    ; Before running this, you should have set up your zprobe Z offset to suit your build, in the G31 command in config.g.

    M561 ; clear any bed transform, otherwise homing may be at the wrong height
    G31 X0 Y0 ; don't want any probe offset for this
    G28 ; home the printer

    ; Probe the bed and do 6- or 7-factor auto calibration
    G30 P0 X-73.6 Y-42.5 Z-99999 ; X tower
    G30 P1 X0 Y-85 Z-99999 ; between X and Y towers
    G30 P2 X73.6 Y-42.5 Z-99999 ; Y tower
    G30 P3 X73.6 Y20 Z-99999 ; between Y and Z towers
    G30 P4 X0 Y67 Z-99999 ; Z tower
    G30 P5 X-73.6 Y20 Z-99999 ; between Z and X towers
    G30 P6 X-36.8 Y-21.25 Z-99999 ; half way to X tower
    G30 P7 X36.8 Y-21.25 Z-99999 ; half way to Y tower
    G30 P8 X0 Y42.5 Z-99999 ; half way to Z tower
    G30 P9 X0 Y0 Z-99999 S9 ; centre, and auto-calibrate 6 factors

    (Go here…. http://www.escher3d.com/pages/wizards/wizardbed.php ) To make your own.

    Put the M557 R150 S20 into your config.g.

    If you want to run the mesh right after the bed calibration, put the G32 G29 at the end of the bed file. It will run the calibration and then the mesh. If you want to manually do them separately, leave the G32 G29 out.

  • administrators

    On a delta printer, G32 probing/bed.g is used for calibration. If you want to ue bed compensation as well, use mesh bed compensation (G29).

  • Ok….

    In my bed.g.... I put G32 at the end.... And erase G29. No?

  • Peirof, I got my numbers mixed up in my last post. I corrected them. Been a while since I actually typed the numbers in instead of just hitting the button that I had to go check them again to make sure I wasn't being confused by what DC42 was saying. 😄

  • administrators


    As David says G32 is used on a delta for Calibration. This is more than just getting a level bed. For a delta to work properly the delta parameters must be correctly configured. That can be done manually but with RepRapFirmware and a Z probe the automatic delta calibration is much quicker and probably much more accurate than can be achieved manually.

    If you have a flat bed plate and don't have other artifacts in the delta printer design/assembly that cause the effector to change height across the build area then you may not need to do mesh bed compensation (G29). That said few printers are built perfectly and few surfaces are perfectly flat. I just say this because it's important to get calibration done properly (G32) before going for mesh bed compensation.

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