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Unresolved Extruder not extruding filament smoothly.

Discussion in 'Troubleshooting' started by Oisin, Oct 18, 2016.

  1. Oisin

    Oisin Member

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    Hi everyone. I've had an issue that's been ongoing for ages but I've only gotten around to looking in to it now.

    I took a video of my extruder extruding 150mm of filament. The gear is turning constantly.

    You can see from the video that the filament is coming out, and then stops and starts again and stops etc... It isn't smooth. I've noticed this for a very long time but was never sure what caused it.

    As you can see from the attached image, the resulting strand of filament isn't a uniform diameter. It has bottlenecks and ribs on it.

    I'm wondering if it could be the hobbled bolt not gripping the filament properly. There's no way to view the bolt as it's pulling in filament so it's hard to tell.

    I've tried tightening the bolts to the max and also at a variety of different levels. They all result in what you see above.
     

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    #1 Oisin, Oct 18, 2016
    Last edited: Oct 18, 2016
  2. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    What type of filament?
    Probably not the hobb...

    Sounds more like PLA micro-clogs, although they usually will get bad enough to completely stop the filament at some point.
     
  3. Oisin

    Oisin Member

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    Well this particular extruder is a brand new V6, so I don't think it's a clog. It's PLA at 190C
     
  4. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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  5. Oisin

    Oisin Member

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    Ah I should have mentioned that seasoning it was the first thing I did. Happened with my last V6 too and that was also seasoned. I use an oiler too.
     
  6. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    Is is supposed to be stopping and starting extrusion as in the video or is it supposed to be one long extrude?

    Not entirely clear on what you are showing us just yet.
     
  7. Oisin

    Oisin Member

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    The video shows what happens when I instruct the printer to perform a single 150mm long extrusion.
     
  8. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    Then I would suggest that the problem is with one of the following:

    1) the extruder stepper driver
    2) the extruder stepper motor
    3) the RAMPS


    I would check them in that order...
     
  9. Toro1966

    Toro1966 Active Member

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    Temp. I had similar issues. Almost exactly the same. Have you tried upping the temp 5-10 degrees and trying again?
     
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  10. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    Good point I had assumed he already did the test for extrusion temp :)
     
  11. Oisin

    Oisin Member

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    I did indeed do that test for extrusion temperature. From 190 to 210 in increments of 5 degrees. It didn't help unfortunately. You would assume it would have helped since you're melting the plastic more effectively which should help fight clogs.

    I'll borrow a temperature gun to make sure the extruder is at the temperature that's being displayed. E3D have a new thermistor so I'm not sure if it's the same as what you'd normally select in the firmware for a V6.
     
  12. danzca6

    danzca6 Well-Known Member

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    The heat gun may not give you an accurate reading. Also yes, the new cartridge thermistor is the same thermistor as before on the V6 just in a cartridge. So setting the firmware thermistor type to 5 is still a valid change to make.
     
  13. Oisin

    Oisin Member

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    I thought it might not. The heater block is pretty small. Fair enough then! Thanks for the info.
     
  14. Oisin

    Oisin Member

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    So I managed to get a relatively consistent flow of filament at around 230C. This is PLA though so that seems odd. There was still some bottlenecking but I was able to print. I tried an overhang test in order to see if my new fan would finally allow me to produce smooth overhangs. I've attached some pictures of the results. I think the deformation might be to do with the temperature I'm printing at. Would you agree or do you think it could be something else? Lowering the temperature brings me back to the original problem. I think I have some retraction settings to play with as well.
     

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  15. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    While someones temperatures are never a good thing to judge by, those are pretty far out of range for PLA.
    I would suspect the thermistor in some way. Not specifically a 'bad' thermistor, but is the thermistor type set correctly in the firmware?
    If you changed the firmwaer did you flush the EEPROM after changing the firmware (M502 followed by M500 ) ?

    If the temperatures are sane then that will certainly explain the issues. Perhaps you should swap nozzles as a test, if clogging was an issue then there may still be something left (something burnt/crispy at this point) partially blocking the nozzle.
     
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  16. Oisin

    Oisin Member

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    Yes I did indeed. I selected the correct thermistor type and I always send M502 followed by M500 when I reupload the firmware for any reason.

    I've had this issue with a few different nozzles though. One 0.4mm and two 0.25mm. I'll go back to my old nozzle and see if it makes any difference.

    Since the only other factors are the hobbled bolt and the filament itself, I might try changing those too. The filament I'm using is about 3 months old now. Not sure if that makes a difference.

    With regards to the pictures, is that defect a result of the heat being too high?
     
  17. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    When the heat get too hot you are going to see degradation in the output. That is about as specific as I can be.Usually (or at least often) this will show up as stringing and layers running, oozing, but not always.

    disclaimer: There are too many factors to simply 'eyeball' a print and say with certainty what exactly is wrong :)

    Having said that, yes... yours looks like it was printed too hot (stringing, poorly defined corners and layer lines, etc)
     
  18. Oisin

    Oisin Member

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    Okay. I've pretty much always printed PLA at 190C so I'd assume that I shouldn't have to move in temperature. Could the oiler cause the hobbled bolt to slip on the filament? The bolt does dig in to it, but since I can't see it in action I can't know for sure. I don't see how the plastic could stop and start like it does in the video while the gears on the extruder are constantly turning.
     
  19. danzca6

    danzca6 Well-Known Member

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    Are you able to take a couple pics of what your hobb bolt looks like? I wonder if you are missing teeth or have some wear/buildup issues.
     
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  20. Oisin

    Oisin Member

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    I'm away from home until Monday so I can't take any pictures of it until then. I haven't cleaned it in a while though so that's the next port of call.
     

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