Why won't my filament feed through the extruder anymore?

  • Printer: Monoprice Select V2.

    I've done several prints already and swapped out filaments many times but in my most recent swap, I can't feed my PLA through any more.

    I first preheat my extruder for PLA temps (185 °C). Then I press the plastic thingy to allow me to push as much of the filament into the hole as possible. Then I adjust my extruder position to try to suck it in. Usually after a few mm, I start to see the filament come out of the extruder and I also feel a pull on the filament from the top. But nothing is happening now.

    However, if I adjust the extruder position in the opposite direction, it eventually pushes the filament back up and out, so I guess the "stepper motor" (is that what it's called?) is working (at least in one direction).

    I'm getting ready to open the extruder module up to see what's going on, but wanted to see if anyone had any simple ideas for me to try before I unscrew anything.

    **Terminology note**: Keep in mind that the *Extruder* is the motion setup that pushes the filament. The part that reshapes the plastic is the *nozzle* which is mounted in the *hotend*.

  • kane

    kane Correct answer

    4 years ago

    I figured out the issue. I think I was shoving it in the wrong hole.

    I took apart my extruder component. There's a good video on it here.
    But basically, you just have to loosen the two bottom screws on the side fan like this:
    enter image description here

    I checked everything out first. I cleaned the extruder head with the included pin. I also shoved the filament through the heated area and filament came out ok.
    enter image description here

    But then I discovered the filament could go in the wrong way sometimes through the extruder.

    This is the correct way for the filament to go through. It should come out of that plastic hole.
    enter image description here

    But once in awhile, I accidentally pushed the filament through this way.
    enter image description here

    If the filament was bent and I pushed the lever too hard, it would often find its way down the wrong path.
    So I played around with how much force I should be holding down the lever and how hard I should be pushing the filament through.

    I don't know if other 3D printer extruder feeders are designed this way, but seems error prone. Or maybe it's just me.

    If you want better prints, remove the spring from the X-axis belt and properly tension the belt by printing a proper belt tensioner. You now have an extra spring in the spring-mass system. Having 2 springs with different spring constants, the displacement of the mass (read hotend) becomes more complex.

    "this thing" is the Extruder comprised of the motor, extruder gear, idler roller and its lever. I have to note though that the extruder looks somewhat sketchy... It might be a good idea to unmount the extruder and champher the feed hole on the incoming side so it has an easier time "fetching" the filament.

    I have two coworkers that each have monoprice printers with these extruder designs - I recommend putting the filament just barely in the extruder and using the "Feed filament" function in your firmware to put the filament where it needs to go. Having the bearing put pressure on the filament against the gear tends to guide the filament better than doing it manually, as I've discovered with quite a bit of trial and error.

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Content dated before 7/24/2021 11:53 AM