Problem with Bed Leveling



  • Hi, I have a problem with mesh bed leveling. I use a Tevo little monster with Duet Wifi and panel due 5. I have now retrofitted the Smart effector 2.0. unfortunately, I get here no reasonable result with the leveling, it come out with each calibration different results. in the attachment times an example picture.
    The heatbed is a PEI sheet with magnetic foil for fixation. I heat up the bed to 60 ° C!0_1561926192842_highmap.jpg
    0_1561926322703_highmap2.jpg

    Here the Config.g:

    0_1561926445424_config.g



  • Here one more Highmap, only 10 Minutes Betwen the others.

    0_1561929864638_highmap3.jpg



  • the 2 images look similar. it looks as though the height is deviating between the two.

    have you done the section "Check Repeatability" from
    https://duet3d.dozuki.com/Wiki/Calibrating_a_delta_printer ?


  • administrators

    The "crinkle crisp" effect (ridges and valleys running along the X direction, with ridges at one end turning into valleys at the other end) is caused by backlash in the mechanics. To avoid it:

    • Lubricate the ball joints. I use a little silicone grease.
    • Make sure the carriages run smoothly on the towers with very little friction
    • Check that the belts are reasonably tight
    • Make sure the motor current is high enough, at least 65% or rated current


  • @veti Thank you for the rpley.
    Yes i think that there everthing is fine, i will build th Tevo back to Microswitch Probe and check the bed again.



  • @flipps said in Problem with Bed Leveling:

    Smart effector 2.0

    Hi flip,
    Maybe you already tried all this , I dont know , I just try to be useful...
    DC will correct me if I'm wrong.
    The Little monster unfortunately , as many delta printers, have not an absolute perfect construction. So there are tolerances.
    For resolve this I made some mod at my printer : https://forum.duet3d.com/topic/8397/tevo-little-monster-duetwifi-touch7-my-conversion/6
    1- changed the belts. Used more rigid with iron cores.
    Here you can see the differences between the two types. https://www.reddit.com/r/3Dprinting/comments/61j9et/i_tested_some_gt2_belts_to_failure_on_a_tensile/
    The standard ones can became loose more than twice the iron ones.
    2- with a 1mm Teflon sheet and some scotch I used to fill the gap between the cartridge and the structure. (now there is zero torsion of the cartridge)
    And tighten up the small wheel using the proper register on the cartridge.
    3- avoid to use grid compensation and full automatic calibration.
    About this I checked manually every single point of the calibration . https://duet3d.dozuki.com/Wiki/Calibrating_a_delta_printer
    At the point "Adding trigger height corrections to the bed.g file" this was for me fundamental.
    ex:
    this is my file , but of course will not be the same as yours!
    ; bed.g file for RepRapFirmware, generated by Escher3D calculator
    ; 16 points, 6 factors, probing radius: 140, probe offset (0, 20)
    G30 P0 X0.00 Y122.50 Z-99999 H0.074 ; 1.255-1.181=0.074
    G30 P1 X80.84 Y96.34 Z-99999 H0.21 ; 1.391-1.181=0.21
    G30 P2 X133.29 Y23.50 Z-99999 H0.102 ; 1.283-1.181=0.102
    G30 P3 X121.24 Y-70.00 Z-99999 H0.084 ; 1.265-1.181=0.084
    G30 P4 X47.88 Y-131.56 Z-99999 H-0.014 ; 1.167-1.181=-0.014
    G30 P5 X-47.88 Y-131.56 Z-99999 H-0.123 ; 1.058-1.181=-0.123
    G30 P6 X-121.24 Y-70.00 Z-99999 H-0.1 ; 1.003-1.181=-0.178 schiaccia troppo quindi -0.1
    G30 P7 X-133.29 Y23.50 Z-99999 H-0.1 ; 0.975-1.181=-0.206 schiaccia troppo quindi -0.1
    G30 P8 X-80.84 Y96.34 Z-99999 H-0.133 ; 1.048-1.181=-0.133 schiaccia troppo quindi 0.05
    G30 P9 X0.00 Y54.44 Z-99999 H0.057 ; 1.238-1.181=0.057
    G30 P10 X51.84 Y29.93 Z-99999 H0.113 ; 1.294-1.181=0.113
    G30 P11 X60.62 Y-35.00 Z-99999 H0.03 ; 1.211-1.181=0.03
    G30 P12 X0.00 Y-70.00 Z-99999 H-0.038 ; 1.143-1.181=-0.038
    G30 P13 X-60.62 Y-35.00 Z-99999 H-0.139 ; 1.042-1.181=-0.139 ???
    G30 P14 X-51.84 Y29.93 Z-99999 H-0.05 ; 1.131-1.181=-0.05 ???
    G30 P15 X0 Y0 Z-99999 S6 ; 1.181 or S9 for diagonal rod calculation and more parameters

    I use a slurry of white glue and sugar pound applied with a sponge. Despite the irregularity of the surface the first level is acceptable even on big objects.
    An other tip. I take at lest one calibration with cold plate and one at hot plate before each print.
    Also for me the maps are not equal but this doesn't effect the printed parts.

    My motor current:
    M906 X1700 Y1700 Z1700 E1700 I60 ; Set motor currents (mA) and motor idle factor in per cent.I100 is idle 100% power motor. By def 1800 for axis and 1500 for Extruder for standard motors. For 0.9 motors use 1700 for 3 axis and 1700 for extruder (the motors are the same)



  • Hi, I have now rebuilt my TLM back to micro switch (thanks to the magnetic rods no problem) and started a new calibration, attached the pictures.
    0_1561982178332_20190701_135028.jpg
    0_1561982187668_20190701_135031.jpg
    0_1561982195133_20190701_135047.jpg
    0_1561982291888_2019-07-01 13.58.02.jpg


  • administrators

    Did you see my post in which I gave the cause of the "crinkle crisp" height map, and possible solutions?

    You should not need to add H corrections to the probe points when using the Smart Effector, or any other type of nozzle contact Z probe. They are only needed when using an offset Z probe on a delta printer, to compensate for any varying tilt of the effector.


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