Solved Filament jammed inside BETWEEN extruder and hot end

Okay, I have a new problem and I don't know how to solve it. Technically, it's 2 problems (the first basically caused the second):

1) I had dark globs of filament gooping onto the prints. Almost caused print fails a couple times (I had to pause it and scrape off the bumps), but mostly just has charred/overheated PLA (I think?) in the print.

2) I wanted to test and see if this is something happening with the printer, or something due to the filament (which worked okay for several prints, then this issue started), so I pulled out that filament and tried to swap back in the Robo Blue that came with the printer. That's when the problems started. I pushed it down into the extruder, and it seemed to be pushing out extrusion of the old green filament. So I start a print, and it fails -- nothing is extruding. Canceled the print and tried to spin the extruder by hand... nothing coming out. So I back out that filament to try with another (wood filament), but a piece of the blue got stuck inside the channel leading to hot end. It wouldn't go down / extrude through when pushed with another filament, so I tried yanking it back out (with hot end on to help loosen things) -- no dice. So then I decide to take my small allen key / hex wrench and use it to poke the filament down in... it went down into the molded plastic hole, but NOT out the other end of the hot end. So, now I am really screwed -- a piece of blue filament, wedged down in that molded channel leading to hot end, but not being able to be pushed through the hot end. I unscrewed the tension screws for the extruder to get better access and see all of this but... how can I get this jammed filament out??

Really bad timing for all of this. Was just about to print a great tablet stand design my students invented (we got a prototype printed, but it had the burnt-globs issue, so wanted to fix that for printing the 2nd iteration. Bah)

This is the first major annoyance/problem I've had with this printer. It's feeling like I'm going to have to completely dissect the print-head extruder/hot-end assembly, and that's a bad feeling.

 

Is there filament leaking out the top of the hexagon nozzle?

If you have fine enough tweezers it may be possible to pull out the filament stuck in the channel. Otherwise it's 2 screws that hold the nozzle on and it's pretty easy to loosen those and let the nozzle drop out. Then you can pull the filament out much easier.

Fixing this on the Robo is SOOO much easier than on the replicator 2x

 

Yeah, eventually I figured this out and removed the hot end, and was able to get to the filament that way.

Only one problem remains: when I reattached the hot end, it doesn't seem to be aligned with the extruder hole, so I can't actually get the filament down into it. Is there an easy way to make small adjustments to make sure the hot end hole lines up perfectly with the extruder? (this may have always been an issue on my unit -- it was always difficult to swap in new filament and get it down into the nozzle, beneath the extruder bolt. I always had to poke it around a little bit. )

 

Hmm I would get a flashlight and look through to make sure. Kinda hard to mess up the alignment on that.

It was always pretty tricky to get the filament loaded. There are some things you can do, like a brass tube, to help with alignment

 

Okay. Trying to shine my flashlight (cell phone light) down through slot in case. Might be easier to do all this if I take off the case, but haven't bothered yet. (anyway, it makes a good spot to lay my phone to shine a spotlight down into the extruder.

Will try to fenagle this and see if I can get it working again. (Removed the screws again, now I can't get the nozzle/hot-end back together... the mounting is a little tight, so the screws were threaded into/agains the metal on either side. Not sure if that is normal or not, but makes it even more difficult to reassemble.

Now I suddenly don't even care about the z-ribbing issue. I just want to be able to print! (Still, I did have to try swapping the filaments, because the burning/extra globbing was a problem. Is it possible for filament to leak from that hot end nozzle area at all?)

 

Well, I give up. Been trying to reseat the thing, get it aligned, and screw it back in for 20 minutes now. Really annoying design here. I like that it can be popped out without complete disassembly. I just don't like that the way it is seat is just sort of "jammed in there", so you have to be sure to jam it back in (the screws, dug into the side of the metal) the same exact way. this makes it extremely difficult.

 

Now I think because of all of this, it has stripped any sort of threading for the screw to grab. The printer may be dead for now. If there was supposed to be threading in the extruder body where the hot end (cold end?) screws mount, then that has been stripped due to the inability to seat the metal end correctly.

Serious design flaw. Pretty disappointed. Not sure why the filament was globbing out and burning up, couldn't even test because can't extract old filament, now can't even re-seat the hot end. Game over.

 

So, now my nozzle head is attached with only one screw (this is not ideal -- it is a bit wobbly; the other screw simply wouldn't seat, and now doesn't thread at all)... I was hoping it might still be serviceable. But the fact of the matter is that I still have filament jammed in the nozzle (the cold end, not the hot end -- thus, it is not melting at all, but is wedged down inside and can't be pulled out)... so I'm at a loss for what to do. I really should have done this very important print FIRST, then futzed with it to see what the leaking/charring filament problem was. Didn't expect a simple filament swap to break the darn thing...

Maybe I need to order a Solidoodle and see how it compares? (as it is, this isn't functional -- I tried jamming a paper clip down into the cold end to push the filament through the hot end while heated -- no go. Is there some sort of very narrow soldering-iron-like tool that could be inserted in to melt the jammed filament? I have no idea how to un-fubar this situation)

 

Okay, one more question (now that my RoBo 3D is, more or less, broken -- unfortunately, it doesn't seem possible to reattach the nozzle properly, but if I can get it attached with one screw that may be enough to be functional -- I'll worry a little bit about the effects of its wobbling, but hopefully I can jerry-rig it to be "good enough"):

How hot can the all-metal nozzle be exposed to? I'm not talking about the hot end with the wires and the rubber square surrounding the heater and thermostat, but I'm talking about the brass shaft and aluminum heat sink (?) around it. That is the part that is all jammed up, and inserting objects to try to "pipe clean" it isn't working at all.

Could I bake this in the oven at 210 degrees to melt the PLA out of it?


Super frustrated about this. I know cleaning and maintenance are going to be required on any 3D printer, but didn't expect it to be so difficult to clean and reattach the nozzle...

(also, any idea how so friggin much PLA got melted up in the rubberized casing around the hot end? That is what is gooping up... maybe it was just little wisps that flew up and re-melted, gradually coating the area. I don't know)

 

Hey @mediaguru I made this and it might help you

 

After dissecting and fiddling with the all-metal end, I've decided I kind of like it -- seems superior to some other printers. But the jamming in the hex part is truly a pain. I ended up baking the hex in the oven at 420 F for a few minutes, and that melted it up enough for me to jam a paperclip through to clear it out (I hope?)
What I DON'T like is the way it is attached with those 2 screws. Really shoddy there. Seems like a simple improvement would be to thread a screw hole directly into the side of the aluminum at the top of the hex -- one single, short screw could go through the plastic and into the metal (ending before getting to that middle brass channel, of course), and would ensure proper alignment and flush and secure fit.

Is there anything like acetone that works for PLA to clean the nozzle?

 

Hmm... maybe I will try the seasoning/oil

But right now, my biggest problem is this: I simply can't get the damn thing back together. It's really ticking me off.

1) The whole metal end assembly would not go back into the plastic encasement (with the 2 screws) -- could only get it to align with 1 screw;
2) Now, even worse, the cold end / heat-break hex section will not screw back into the hot end block. When attempted, it simply strips the threading from the hot-end (which seems to be an aluminum block, thus soft metal and easy to strip)... so, now I am REALLY screwed.

Well, I got a good dozen prints (sort of, except for the z-ribbing) out of this thing.

I guess you get what you pay for. I was just about to post a review saying how, overall, I was pretty pleased with it. Guess I am going to have to amend that, because there is no reason I should be having this much difficulty with something as necessary as cleaning and re-inserting the hot end.

Really, really, really wish I'd known this was going to happen. I would've printed that one final crucial model before trying to swap to another filament.

Isn't there some sort of parts-replacement warranty for this? Looks like I am going to need new pieces to get my hot end working again...

 

Thanks for the video. I was able to figure out most of that (didn't remove the brass insert, but didn't need to after all); once I heated it, it became easier to clean out. Problem is, when I tried to reassemble, the brass threading stripped/galled the aluminum heat block, so I'm not sure if I can get it to seat properly/tightly at this point, which means I am just going to have (probably even worse) jams/backups/leaking at this point. I guess I needed to have the hotend heated the whole time I was trying to screw the cold end into it, maybe that would've helped. I think I might need to get a replacement heating block/mount now.

Going to try to stick it out and see if I can get it fixed. I liked the RoBo quite a bit up until these recent problems... I do hope they can find a somewhat more streamlined way of attaching the hotend back on. (or maybe I can do it myself)

Do you know if there's anybody I can contact to try to get that aluminum heat block replaced? (I don't need all of the hot-end parts, which is why I don't want to go buy a whole new Hexagon... just that one little part which has stripped threading now)

 

Can you post a picture to show the damage? I'm surprised youre having so much trouble. You know you can rotate the nozzle a little bit and tap new part of the hexagon

I don't know of anyone that sells replacement hexagon parts

 

Yeah, thanks for the help guys. Just ordered one (er, several, because they end up being 50% of the price each when you buy in bulk and factor in flat-rate shipping that is $25 for one or $25 for ten, at -$14 discount each as well) last night. Fingers crossed!

I just hope next time this happens (because I'm sure it will, unfortunately -- although I'm going to try to keep it tightened while hot on the machine from now on), I can find a way to clean the jam without so many problems and without actually breaking the hotend.

If I keep having issues, might try a different hotend. This one was working like a champ until the leaking started, though

 

Using the oiler seems tricky (to ensure not too much oil stays on the filament, which would cause problems with sticking, gaps, etc. I assume..., but one thing I might try is seasoning the inside with some oil. That sort of "natural teflon" coat seems like it could be a good idea. On the other hand, if it's too thick of a patina, I suppose that could cause problems, too...)