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Partially Solved Bowden Upgrade for Robo 3D R1 lead screws upgraded

Discussion in 'Troubleshooting' started by Luis Olivet, Mar 23, 2018.

  1. Luis Olivet

    Luis Olivet Member

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    Hello friends, a thousand apologies for writing in Spanish. recently ordered by amazon the following article

    [​IMG]


    Well, I want to update my printer to the BOWDEN system ... my problem is that, when I print, if I use the normal configurations of the printer, it turns out that it is too much filament, so I did a little research and I found that, change the configuration of STEP PER MM of the normal 250mm to 148mm ... I tried it and the print always took a lot of filament ... then with a ruler, I started to take measurements and lower the STEP per MM until reaching the number of 100 step, which causes the extruder to pull exactly 10mm when I give the order to extrude 10mm ...

    upload_2018-3-23_16-12-54.png


    My big problem is that in the printing process, there comes a time, where the extruder starts to thunder, it makes a crack, like when the printer is CLOGGED ... and if the printing does not stop, that actually happens. it gets stuck, but this does not happen, if for example I put 135 steps ... I do not know if I should modify something in the firmware (with IDE arduino) or what I have to do to make it work, if I have to modify something else or what I have to do, please friends help .... I LEAVE SOME IMAGES:

    upload_2018-3-23_16-11-8.png

    upload_2018-3-23_16-11-29.png

    upload_2018-3-23_16-11-55.png

    upload_2018-3-23_16-12-14.png

    upload_2018-3-23_16-12-23.png

    upload_2018-3-23_16-12-40.png
     
    #1 Luis Olivet, Mar 23, 2018
    Last edited: Mar 24, 2018
  2. Luis Olivet

    Luis Olivet Member

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    this a printer test with small cube (the problem happens, when i put print a large print)...


    upload_2018-3-23_16-28-27.png
     
  3. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    Not sure I completely understand the issue, but let me make some generic/general comments about Bowden.
    1) The PTFE tube used will add backpressure to the extruder. The longer the bowden tube, the more backpressure the extruder will see.
    2) Most bowden extruders (like yours seen in the pictures) are not geared extruders, but rather they are direct extruders. This means that they can tolerate less backpressure.
    3) Too much backpressure will cause you to not extrude the correct amount of filament because the extruder will start skipping steps.

    This tells me that the steps are set correctly which is a good thing. If you see issues as it begins doing longer prints it is probably too much backpressure. You can swap to a geared extruder which will help (but you will need to re-calibrate the Z steps if you do that).
     
  4. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    We have one printer (a delta style) with a 6 foot bowden feed. It was (and still is) a problem to keep it feeding correctly with a direct extruder. We moved to a geared one (a GregsWade) at one point (which helped) and finally ended up going with a different PTFE tube that is supposed to be less friction and swapped back to the direct extruder. We have not used it enough to say if it is a reliable fix, but it does work.
     
  5. Luis Olivet

    Luis Olivet Member

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    hi tanks for aswer... my PTFE tube, have no more of 20CM of lengnth.... so i dont think it can be the problem (really when i do the change, i left like 40cm for the tube... but i think maybe is too large... for that i cut it to 20CM)...

    i found a not so good fix, but it work (not perfectly but work) i raise the heat. from 210 (PLA) to 225'C... with that. it Dont clog any more... but still sound forced spin mottor.. i will try all your suggest, i hope it can be done... tanks again friend
     
  6. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    Raising the temperature is not a bad idea. Our delta (long bowden feed I mentioned) runs 15-20 degrees C hotter when extruding as well.
     
  7. Luis Olivet

    Luis Olivet Member

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    Yep.. but i think i go to GreWade Extruder... but bowden. i see one on thingiverse... i hope it fix my problem :) tanks a lot @mark tomlinson
     
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  8. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    When we converted our long bowden to a gregs wade it helped. It will take some calibration to get the steps right, but it has enough torque to deal with the extra backpressure.
     
  9. BrooklynBay

    BrooklynBay Active Member

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    I have my Gregs Wade set up with a short piece of PTFE tubing so that flexible filaments don't get tangled up in the hobbed gear. It works fine for a while then it starts to bind. I did some research, and found Capricorn tubing. They make two different types. It seems to be working fine since I swapped this for the regular PTFE tubing. You could try this, then let us know how it works.
     
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