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HELP! Can't load filament  

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Ira S
(@ira-s)
Trusted Member
HELP! Can't load filament

I've been printing with my MK3 for over a year. Today I tried to change filament and can't get new filament to load.

It will start to load, and move 88mm of filament, then can't move any more. That puts the end of the new filament midway down the "heat sink" area of the extruder. I'm running PLA.

I've tried cranking the extruder temp up to 290.

I've tried different filaments.

I've tried trimming the end to a V (as opposed to my normal slant cut).

Nothing has cleared it.

Short of taking the entire extruder apart, any suggestions on how to clear this?

Thanks.

Opublikowany : 11/04/2019 4:37 pm
davep
(@davep)
Trusted Member
Re: HELP! Can't load filament

Is it doing the famous clicking when trying to load the filament?

You may need to take it apart (somewhat).

When this happened to me, I removed the nozzle and took an unfolded paperclip and stuck it in from the bottom. I was able to push a stuck chunk of filament that was above the heater (and obviously) not melted to clear the jam.

Just follow the directions from Prusa on removing the nozzle and you should be able to clear things out.

-Dave

Opublikowany : 11/04/2019 5:03 pm
Ira S
(@ira-s)
Trusted Member
Topic starter answered:
Re: HELP! Can't load filament

Do I need to remove the hot-end from the extruder assembly to do this?

Opublikowany : 11/04/2019 5:51 pm
gnat
 gnat
(@gnat)
Noble Member
Re: HELP! Can't load filament

No, just remove the nozzle itself. Once the nozzle is off you may then be able to run the temp up high and poke the clog out with filament, otherwise pushing it back out the top might be your only path.

I'm having similar issues with a print right now. My steps (PLA) are:

1) Heat to PLA temps
2) remove nozzle
3) raise extruder temp to 270 or higher
4) give it a few minutes after getting to temp
5) feed scrap PLA through normally
6) watch hardened blob of PLA pop out
7) Cool back to PLA temp
8) take heat gun to nozzle to clean it up if it is gunky
9) reassemble and re-try print
10) Unfortunately, repeat as needed 🙁

I did try skipping the nozzle removal step, but the issue returned when I tried the print again. With removing the nozzle I was able to get a full print done and it failed again a few hours into the next print.

If you don't have a MMU (and don't plan to), watch the video that was shared with me here: https://shop.prusa3d.com/forum/hardware-firmware-and-software-help-f64/jammed-and-i-don-t-know-why-t28867.html#p137325

In my case my problem prints have a lot of retractions so the heatbreak might be my issue.

MMU tips and troubleshooting
Opublikowany : 11/04/2019 6:13 pm
Ira S
(@ira-s)
Trusted Member
Topic starter answered:
Re: HELP! Can't load filament

Thank you "david.p87" and "gnat".

I basically followed your suggestions and I'm back in business. What I did was:

1) Removed the nozzle per your instructions (remove fan, preheat for PLA, remove nozzle). There was no filament loaded (other than the jam).
2) Raised temp to 270.
3) Used a very small Allen wrench to push up from the bottom. It did encounter resistance, but I was able to push though.
4) Loaded filament with nozzle still removed - filament loaded successfully and flowed freely from the hot end.
5) Unloaded filament and re-installed nozzle.
6) Loaded filament again and got good flow from nozzle.
7) Reassembled fan.

What I'm not sure about was whether I actually pushed the clog up and out of the PTFE (?) tube, or just dislodged it so that the new filament was able to push it down and out. If I did push it up and out of the PTFE tube, not sure where it went.

I'm now printing my first print on the brand new Textured PEI sheet that I just received (finally).

Thanks again.

Opublikowany : 11/04/2019 10:23 pm
gnat
 gnat
(@gnat)
Noble Member
Re: HELP! Can't load filament

Did you have the idler door open while you did this? If so you should have seen the blockage come out if it did. If you didn't have the door open, open it and take a look.

If you can't find the plug then I'd guess that you just poked a hole through it and it will re-clog soon enough. Maybe try some cold pulls to see if you can get it all out.

Another hint that I would offer, when trying to clean out the nozzle, use a different color filament than what the clog likely is. In my case the clog was silver and I used blue filament to help clear the jam. This made it easy to tell that it was the blockage when it popped out onto the PEI sheet.

MMU tips and troubleshooting
Opublikowany : 11/04/2019 10:46 pm
davep
(@davep)
Trusted Member
Re: HELP! Can't load filament

Sorry - been busy and didn't get back to this.

I have the idler door open when I do this to make it easier to clear the tube, so to speak. 🙂

Sounds like you got it worked out. None of my allen wrenches were long enough, so the unfolded paperclip worked perfectly (I was able to see it come all the way out the top by the open idler door).

-Dave

Opublikowany : 11/04/2019 10:51 pm
Ira S
(@ira-s)
Trusted Member
Topic starter answered:
Re: HELP! Can't load filament

Thanks for the additional information. I will open the idler door and check to see if there's something I pushed out that's loose in there.

While I didn't use a lot of force to move the stuck filament, it did require some. Is there any chance I displaced the PTFE tube (pushed it up)? The printer is working. I guess when I get to opening the idler door I'll see if the tube is too high, but if there's a chance I moved the PTFE tube, I'll check sooner than later.

Opublikowany : 12/04/2019 4:38 pm
gnat
 gnat
(@gnat)
Noble Member
Re: HELP! Can't load filament

I think you'd already know. I bought mine pre-assembled so I assume the tube is installed correctly. If so then it it was pushed up at all it would impact the idler and I would expect noise if nothing else.

MMU tips and troubleshooting
Opublikowany : 12/04/2019 5:27 pm
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