Bed leveling with 3 independent z screws

  • 2 z screws on the left side and one on the right side + BlTouch running Duet3

    Anyone want to share settings for this?

    Status today (railcore inspired printer) :
    All axis ok
    X and y limit switch ok

    Waiting for the tool board for the extruder.. wires

    BlTouch ok1581582041169-corxy.jpg

  • Hi.
    Sounds like this is similar to a RailCore.

    This what we use for levelling.
    M140 S75 ; Raise bed temp to profile requested bed temp
    M104 S150 T0 ; Raise hot-end temp to 150C for G32 auto-calibration
    M190 S75 ; Wait for bed temp to rise
    M109 S150 T0 ; Wait for hot-end temp to rise to 150C
    G28 ; home all axes
    G32 ; Autocalibrate bed
    G32 ; Autocalibrate bed a second time
    G32 ; And a third time ( for 4 point probe)


  • You also need to make sure your leadscrew locations are defined.

  • My Bad! Forgot to say we use this in our slicer config!
    If you look at there are base configs for the Duet2.


  • I have a very slightly different setup, two "in front" and one in "Center back". I believe you can update this fairly easily.

    Relevant statements extracted from config.g:

    ; Driver to axis mapping
    M584 X0 Y1 U2 Z3:4:5        ; X and Y for CoreXY.  U for toolchanger lock. Z has three drivers for kinematic bed suspension. 
    M569 P3 S0                  ; Drive 3 direction | Front Left Z
    M569 P4 S0                  ; Drive 4 direction | Front Right Z
    M569 P5 S0                  ; Drive 5 direction | Back Z
    ; Leadscrew locations (really, kinematic coupling locations) extracted from CAD model assuming back right build plate corner is (0, 0)
    M671 X300:5:152.5 Y316:316:-14 S10 ; Front Left: (300, 316) | Front Right: (5, 316) | Back: (-14, 152.5)
    M350 Z16 I1                       ; Set 16x microstepping for axes. Use interpolation.
    M906 X2500 Y2500 Z1000 E1250 I30        ; Motor currents (mA) and Idle percentage
    M201 X600 Y600 Z10 E1000 U1000          ; Accelerations (mm/s^2)
    M203 X25000 Y25000 Z400 E4000 U10000    ; Maximum speeds (mm/min)
    M566 X700 Y700 Z2 E3000 U200          ; Maximum jerk speeds mm/minute
    M92 Z3200                               ; Steps/mm for Z - TR8*4 / 0.9 deg stepper

    And bed.g (note that front left is a little offset in Y because of a temporary thing that blocks that corner of the bed):

    G0     X152.5 Y40 H1 F10000
    G30 P0 X152.5 Y40 Z-99999       ; probe near back leadscrew
    G0     X275   Y260 H1 F10000
    G30 P1 X275   Y260 Z-99999      ; probe near front left leadscrew
    G0     X25    Y315 H1 F10000
    G30 P2 X25    Y315 Z-99999 S3   ; probe near front right leadscrew and calibrate 3 motors
    G1     X0     Y0 F10000

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