Extruder skipping

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    I’ve received my sigma for a few days, and had been struggling to get any good result.
    Both of my extruder sometime fail to grab onto the filament and unable to feed or retract.
    when I was able to unload the filament, it seems like the section near the wheel is grinded away by the wheel, so the wheel was not able to grab onto the material.
    Does anyone know why does this happen and how to solve it?
    Ive tried fasten and loosen the tension spring, but unclear what it does to the feeding wheel, can someone explain how the tension spring works?



    The more you screw in the screw the more the spring compresses pinching the filament harder against the drive gear. Unscrew the set screw so it is flush with the aluminium edge and give it 2 clockwise rotations that should be a good starting point
    What I would do:
    1. Remove the filament using the menu
    2. Clear the hotend by filament cold pull see the link http://www.bcn3d.com/sigma-maintenance/#break-nylon-cleaning ( if you dont have nylon cold pull with PLA works too but not as good. Pull at nozzle temp 60 degrees)
    3. Check if the drive gear is clean, if the teeth are filled with filament dust from the previous grinding then try to clean it as it wont be able to grip the filament.
    3. Insert filament using the menu
    If the insert works and you can purge comfortably filament using the menu ( on the touch screen “Utilities” –>”Filament” –> “Purge”) then try to print
    Let us know how it goes 🙂


    “3. Check if the drive gear is clean, if the teeth are filled with filament dust from the previous grinding then try to clean it as it wont be able to grip the filament.”
    Are there any instructions anywhere on this? I think I need to have a look at this on my sigma too.


    Thanks for the help EmvioEng, I was able to get the filament out, clean the hotend, and the machine seems to be working fine.
    I do notice the drive gear is filled with dust, probably from excessive tension.
    I’d love to have an instruction on clearing the drive gear.


    Had the same issue when my machine arrived last week, loosens the spring and was better but not perfect. I had manually advanced the filament past the drive gear at first but had 2 failed prints due to grinding and the filament advance all together. I cleaned out as much dust as I could by flushing filament through but I am sure there is some on the gears.

    roger uceda

    I would recommend you to apply heatsink paste in the heatsink. Have a look at this post:

    BCN3D Sigma E3DV6 Hotend Adapter Next


    Only moments ago, I had a less than ideal feed situation. I performed the above steps and applied thermal transfer paste. I used what some will call a strap wrench, others might call it a universal oil filter wrench. It rotates effectively only in one direction, depending on which side is up, so note the arrow. When flipped in the correct position and the strap pulled tightly, it’s practically impossible to damage the fins.

    Can someone provide a hint for putting a photo in a post as an image? I’ve clicked on the img button and provided the copied/pasted dropbox link, but no photo appears, hence the direct dropbox link now presented.

    • This reply was modified 5 months, 3 weeks ago by artesans.

    @ fred_dot_u: First of all the picture must be located in the “Public” folder. In Windows you have to do right click and select “Copy public link”. In the forum you need to press “img” button and past the dropbox link into the 1st window. In the second window you can choose any useful name.

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