Mesh Bed Compensation, doesn't change Z-Height during Print



  • Hello,

    i am actually try to set up my Delta with the Duet v0.85. I use a Z-Probe P4 type and get good results at the Bed leveling, which means the Heighmap is level and at the right position at the Z-axis.
    I also followed the steps form the Mesh Bed Compensation Tutorial to set up trigger heigt ...

    For the next step i tried to set up the Mesh bed compensation. Everything looks just fine but when i start a print, it seems the Z-heigh doesnt change at all.
    I also ran the M122 command and checked if the Bed Compensation is enabled, and it is.

    Here the results od the M122 comand:

    • === Move ===
    • Hiccups: 8, StepErrors: 0, LaErrors: 0, FreeDm: 72, MinFreeDm: 20, MaxWait: 203329ms, Underruns: 0, 0
    • Scheduled moves: 2378, completed moves: 2371
    • Bed compensation in use: mesh
    • Bed probe heights: 0.000 0.000 0.000 0.000 0.000

    So my next gues is that at the point "Bed probe heights" there should be the saved values from the G29 compensation. And becaus they are all zero, the printer doesn't change the Z-axis during the print?

    I'll be glad for any advices.


  • administrators

    The "Bed probe heights" don't relate to mesh bed compensation.

    If the height map is fairly flat then it can be difficult to see any Z movement. To test mesh bed compensation, I usually put a piece of PCB or similar on part of the bed before probing, to create errors large enough to see.



  • Thanks for your reply, i will try it like you mentioned.

    But don't you think it's a little suspicious that the values of the Bed probe heights are all zero?

    And also when i start a print it, the nozzle height is clearly not constant above the Brinting bed. More than 0.1mm. So i expacted the Mesh bed compensation to compensate this offset.


  • administrators

    @philipp-r said in Mesh Bed Compensation, doesn't change Z-Height during Print:

    But don't you think it's a little suspicious that the values of the Bed probe heights are all zero?

    No, those probe heights have NOTHING TO DO with mesh bed compensation. After you run auto calibration, they will be the height errors of the first 5 probed points.

    And also when i start a print it, the nozzle height is clearly not constant above the Brinting bed. More than 0.1mm. So i expacted the Mesh bed compensation to compensate this offset.

    If your probe is offset from the nozzle, then that's almost certainly caused by the effector tilt varying with XY position. See https://duet3d.dozuki.com/Wiki/Calibrating_a_delta_printer.


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