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Gantry vs Belts vs Step motors what is the problem

Discussion in 'Troubleshooting' started by Ian Schilf, Feb 8, 2021.

  1. Ian Schilf

    Ian Schilf New Member

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    Hello all.

    I am an industrial technology teacher in Montana. I have 2 Robo R2 printers and both appear to be acting up. I will go over the individual machines symptoms.
    Machine 1
    Prints lean hard on Y axis. On a 45mm tall print the lean is approximately 10mm.
    The machine is making a grinding noise on a x axis but not under manual control. Only when it is orienting the nozzle to the bed before printing begins. While watching the belts they are moving freely. I am watching the x step motor and seeing the backside of the x motor shaft kind of pulse in sync to the noise I am hearing. Could the motor be on its way out the door? I am looking at replacing the step motor to gantry belt but I am not sure if that is the solution. Any help would be helpful.

    Machine 2
    Same grinding noise as M1 on the x but without the lean on Y.

    We have redone the bed calibration multiple times, and the z offset, I have rehomed them. I have also checked for software updates. I have printed the gantry alignment tools on my other printer and begin that process but I do not think it would cause the grinding noise.

    Any help would be greatly appreciated.

    In Over My Head in a Montana Classroom
     
  2. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    Grinding is usually the endstop (one of them -- which ever axis is grinding) not getting triggered.
    My C2 had issues with the Y axis endstop getting knocked out of position.

    Sanity check them
     
  3. Lance Weston

    Lance Weston Active Member

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    To get a vertical lean the two 12mm rods have become not square to the gantry. I do not see how that can happen, but I would check to see if something is loose in that path. I am having trouble with the grinding noise. Is the noise only when the head is homed? That would absolutely be the endstop switch not triggering. Otherwise it would either be the flange bearings which are not visible or a stepper motor with a failing bearing. Go to the LCD home then motor controls and turn off the motors. Now move the head around and see if it moves freely in all places. If it does it is probable a flange bearing that is failing.
     
  4. wuidling

    wuidling Member

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  5. Lance Weston

    Lance Weston Active Member

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    Your flange bearing is shot. Remove the carriage assembly from the top, I think there are 10 screws of different lengths so keep track. * around the top and one next to each stepper. Unplug the cables from the endstop switches in the back left. Unplug the stepper wires from the steppers. Remove the flat cable from the top of the print head. Now remove the carriage. Partsbuilt.com has the flange bearings. Replace all 8 bearings. Reassemble.
     
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  6. wuidling

    wuidling Member

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    Thanks, removing the top was not a problem, but i have to find another solution because partsbuilt shipping costs to Germany are 50 USD. I think i will repair it with short standard bearings.

    Regards


    Excuse my school english.
     
  7. Lance Weston

    Lance Weston Active Member

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    You have to use flange bearings. Do not lose the two trim washers where the gears directly meet the bearing. I would try to do as little disassembly as possible, just sliding the shaft enough to put on the new bearing. It is a pain in the butt to figure out the correct placement of the spacers and they are best left where they are. The flange washers lock the shafts in place. Somewhere on the R2 forum I posted that not all flange bearings are the same and I gave this link for Ebay and motor quality bearings. https://www.ebay.com/itm/303359820363

    My Grandmother was born in Busum Germany. Glad to help a distant compatriot.
     
    #7 Lance Weston, May 17, 2021
    Last edited: May 17, 2021
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  8. wuidling

    wuidling Member

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    Thanks a lot for the helpful link and the description of the bearing.
    I found a seller in Germany.

    Greetings from Munich.
     

    Attached Files:

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  9. wuidling

    wuidling Member

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    Hello, unfortunately i have to dissamble all parts of the top chassis because the bearings are rough (extruder block).

    Pictures

    So this is a oppurtunity to change some parts posted in this threads:

    http://community.robo3d.com/index.php?threads/carriage-spacers-for-the-r2.23806/#post-139023
    http://community.robo3d.com/index.php?threads/graphite-plugged-bushings-for-r2.23707/#post-138283

    Has anyone done this modification:
    https://www.thingiverse.com/thing:3498414

    Are there any CAD/Fusion original files for the extruder bearing block ?

    Regards

    Excuse my school english
     
    #9 wuidling, May 23, 2021
    Last edited: May 23, 2021
  10. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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  11. Lance Weston

    Lance Weston Active Member

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    I posted that and it works but it requires everything to be printed ABSOLUTELY perfect. I no longer use it myself because it does not provide an improvement worth the trouble. I would purchase NSK or similar high quality bearings instead and keep what you have. If you have not taken the whole gantry apart then don't. A set of replacement spacers where each are labeled as to where they go. will save your many hours of frustration.

    Slide the shafts one at a time, just enough to replace the bad part. Align after completion.
     
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