UM2- How to unclog feeder?

[banooch 0]

My UM2 stopped feeding PLA through the nozzle. I tried to use the "change material" function on the printer to see if something was clogged.

Right away I could tell that the feeder had ground up the PLA and none of the PLA would move in or out of the feeder, even with the feeder moving to help my efforts.

I'm looking in the manual under troubleshooting and it says "Release the pressure on the feeder a bit by adjusting the build plate screw clockwise." I'm not exactly sure how twisting the build plate screw helps since it's not connected to the feeder helps, but I tried anyway and it did not loosen the PLA.

Can anyone give me some advice on how I should be opening up the material feeder to get the PLA out?

 

[nick-foley 5]

Grinding filament is rarely the source of the problem; it is much more likely just a symptom and you have some sort of blockage in your hotend. I would start there.

 

[gr5 2,265]

Well...

I have never had to do this. One option is to remove the bowden from the print head. Another is to take the feeder apart. If you remove the 4 screws on the feeder note that the feeder motor will fall. You can hold it up with a finger below it but you might just want to remove the cover over the stepper first.

Alternatively it's easier to remove the bowden from the print head. Remove pressure first. It's easy to damage the bowden as the little device that holds it in has 4 metal blades and if you pull too hard the blades will scrape away the outside of the bowden so be gentle. Loosen the 4 screws quite a bit and also remove that red clip (either order) then when it seems loose, push down on the bowden holder ring and pull up on the bowden. You probably want the head at 90C to 100C when you do this so the filament comes up also.

Then you can pull on the filament from that end and maybe get it all out.

 

[banooch 0]

Oh man, this is making me nervous since I'm a newb. Does anyone know of a video or set of pictures that shows how to do that?

 

[banooch 0]

OK, I can now confirm due to impatience that taking apart the feeder is NOT a good option EVER.

Seriously, you need like 3-4 hands to put that thing back together. Although I did get lucky with just my two.

OK, now I have to try the bowden tube method except that gr5 scared me with the "blades" comment. Seriously, does anyone have pics or video of doing this routine?

 

[IRobertI 521]

So you couldn't free the filament even with the feeder disassembled? Your head is up to printing temp when you're trying to pull it out I hope? Also, after having taken my feeder off and putting it back on about 20 times I don't find it too difficult

On the top of the print head, where the bowden tube enters the head it goes through what looks like a white plastic ring. Around that ring is a red or blue horse shoe looking thing. Remove that by simply pulling it to the side. Now press down on the white ring so that it pushes against the black plastic of the head. Now the bowden should be free to move up by pulling on it.

The metal blades gr5 talks about are inside that white piece. They act sort of like a one way valve, when the horseshoe is in place the bowden can move down but if you try to pull it out those metal blades dig in and prevent it from moving (which is essential for the machine to work). If you're careless and don't properly release these by pushing down on the white piece you can scrape the bowden so that it becomes harder for them to do their work (or the blades can become clogged with plastic). Doing this once or twice shouldn't be an issue but if you keep doing it there's a risk that they are no longer able to do their job and the bowden will refuse to stay in place which means you can no longer print. If this should happen you can simply cut off a centimeter or two of the bowden so that the blades get a fresh surface to bite into.

 

[banooch 0]

Thanks so much for the clear instructions!

I finally was able to get the PLA out, but only after removing both ends of the bowden tube. The feeder had crushed the PLA so much that it actually kept the PLA from coming out of the top hole of the feeder, no matter how hard I pulled on it. It wouldn't work in reverse either to get it out.

I'll probably make a short video tutorial for other beginners so they can reference it. I imagine that this happens more often than not to people, especially with bad extrusions.

 

[gr5 2,265]

I went about 2 months before I had to take the bowden out the first time. But I've probably done it 10 times now.

 

[gr5 2,265]

Do you live near NYC banooch? Did you go to the 3dprintshow there? Or the makerfaire? If so maybe we met in person.

 

[banooch 0]

I'm actually in San Jose, CA. Born in NYC though, so a fan of NY teams… thus the Yankee hat on my avatar! Have not made it to any 3D trade shows or fairs yet. Will try to get to one out here soon.