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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.

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    $\begingroup$ 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. $\endgroup$
    – Trish
    Commented May 30, 2019 at 17:37

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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.

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    $\begingroup$ 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. $\endgroup$
    – 0scar ♦
    Commented Jan 17, 2019 at 7:17
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    $\begingroup$ "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. $\endgroup$
    – Trish
    Commented Jan 17, 2019 at 9:03
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    $\begingroup$ 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. $\endgroup$
    – Nach0z
    Commented May 30, 2019 at 17:40
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Maybe some PLA is stuck in the throat above the heat break. Can you feed a very small wire all the way through it, or see light through the filament path?

185 is a little on the cold side. I would suggest trying to feed at 195 before taking more drastic measures.

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  • $\begingroup$ I even have some PLA that recommends a temperature between 210-220C $\endgroup$
    – You'reAGitForNotUsingGit
    Commented Jan 15, 2019 at 22:39
  • $\begingroup$ 183 is the coldest I've ever managed to go. For filament I haven't tried before, I'll usually start at 200 or 210, then come down in 5 degree increments until I start to see symptoms of it being too cold, then back up in 1 degree increments until those symptoms go away. $\endgroup$
    – anaximander
    Commented Jan 16, 2019 at 16:09
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Try turning the temperature up to 260 °C and pushing it through.

Also, cut of a few centimetres for I'm the end of the PLA in case the drive wheel isn't able to grab it due to a greasy bit of filament.

If you get it all working, run cleaning filament throughout it and to a cold pull with it. That removed an annoying but of grit from my Monoprice.

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    $\begingroup$ Although raising the temperature is encouraged, 260 ℃ is pretty high for PLA, in case of PTFE lined heat breaks the general advice is not to go above 250 ℃ to prevent degradation of the liner. $\endgroup$
    – 0scar ♦
    Commented Jan 16, 2019 at 16:06
  • $\begingroup$ @0scar I've got the same machine as he does. Printing a few centimetres of PLA at that temperature is what's recommended in the manual. $\endgroup$
    – BanksySan
    Commented Jan 16, 2019 at 19:53
  • $\begingroup$ Could be possible if it is a few cm, but if you are dealing with a hard to remove piece of filament that is stuck higher up or longer and broken off, you would need to wait longer for the clog to get loose. If it has no PTFE lining, like an all metal hotend, my reasoning does not apply. Thanks for the info! $\endgroup$
    – 0scar ♦
    Commented Jan 16, 2019 at 20:05

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