Question about tower adjustments or bed slant



  • Hello,

    I have a delta with a 9" glass/aluminum heat spreader. I am not sure if the towers are slanted or the bed is… with the current numbers I can get a standard deviation of .200 and no better.

    Diagonal 276.800, delta radius 144.446, homed height 316.696, bed radius 120.0, X -0.202°, Y -1.556°, Z 0.000°

    While doing the grid G29 I get poor numbers

    Number of probe points: 303
    Probe area: 314.2 cm²

    Maximum deviations: -0.510 / 1.937 mm
    Mean error: 0.573 mm

    RMS error: 0.738 mm

    I ran height tests using a feeler and came up with the following offsets at each location of the bed (supposed to be .25 at each location)
    .90 at X120
    .70 at X-120
    .25 at Y-100
    .60 at Y100
    .25 at X0Y0

    So I guess my question is… what are the best things to fix/tweak/configure to get a level print? I suspect the G29 grid is too far off to be useful as my prints are still not fully adhering to the bed at all points.

    Thanks
    Jim


  • administrators

    If you are using the IR sensor or any other probe that is offset from the nozzle, and the effector is tilting significantly as it moves in the XY plane, then you won't get good results from G29. You need to improve the geometry to eliminate the tilt. See https://duet3d.com/wiki/Calibrating_a_delta_printer.



  • Its a case of verifying your mechanical setup, and probing method before reading anything into the probing results.

    Try an effector tilt measuring device http://www.thingiverse.com/thing:1369444 i.e. a largish printed triangle face one side parallel to the bed, fix the other to the effector and move around with the triangle a few mm's off the bed. turn it 90 degrees and do it again at various points. You will soon see if its effector tilt, usually worse away from the centre.

    If you cannot eliminate it by improving the geometry of the arms, carriages, towers and effector, try getting your probe as close to the nozzle as possible. Or even remove the hot end, position the probe where the nozzle used to be and probe again.


  • administrators

    Another way to observe effector tilt is to use a bullseye spirit level


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