Print Dimensions



  • Hi,
    I have a kossel mini i have put a duet wifi in, am using an IR probe for bed leveling.
    The problem i am having is i will upload a stl of my design, ie: a simple triangle, and the first print is dimensionally accurate, but subsequent reprints are 2-3 mm smaller.
    Deleting the file and re-uploading produces the same results.
    I have g28 and g32 in my slicer config.
    any ideas would be greatful?

    thanks.


  • administrators

    You can test to see what changes G32 is making to your calibration (it should make it better, not worse!) by running it multiple times and sending M665 to see the changes. It sounds like one possibility could be that your starting calibration for the first print is OK but for some reason its getting less accurate?



  • Thanks for the reply. - I ran two g32,s and did an M665 in between and you are correct, there is quite a variation. Im a bit lost now ....

    --------snip
    10:35:21 AMM665
    Diagonal 224.846, delta radius 124.715, homed height 210.551, bed radius 85.0, X -0.535°, Y -0.678°, Z 0.000°
    10:34:52 AMG32
    Calibrated 7 factors using 16 points, deviation before 0.092 after 0.072
    10:33:52 AMG28
    10:33:19 AMM665
    Diagonal 219.065, delta radius 123.289, homed height 210.595, bed radius 85.0, X 0.060°, Y 0.254°, Z 0.000°



  • Perhaps the nozzle or sensor or some other part is just a bit loose? So it all seems stable, but during the motion of the print or the subsequent g32 (how many points is that probing?) the joint moves slightly and is reflected in the calibration. I don't have a delta yet 🙂 but maybe the arm length changing slightly?



  • Dont use the 7 factors Calibration. It will change, as you can see, the Rod lenght. it changes from Diagonal 224.846 to Diagonal 219.065 and with each change there the dimensions of your whole print will change.
    Solution: use the 6 factor Calibration because it will leave the Rod lenght untouched.
    Calibratting a Delta



  • @barracuda72 thanks !! this was the answer 👍 👍



  • dont forget to delete the config_override, then a new calibration and a M500 to generate a new override file. Should be the mesured delta rod lenght in the override file then


 

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