Oh no! Problem ejecting filament  

Re: Oh no! Problem ejecting filament

https://help.prusa3d.com/l/en/article/WWVRzOY1dX-clogged-nozzle

Look there. Many options. The wire through extruder process helped me in exactly your situation.

Re: Oh no! Problem ejecting filament

Open up the extruder housing using the 2 screws on the left as viewed from the front. You may be able to see the filament sticking out of the PTFE tube below the extruder gears. Try to pull it out with needle-nose pliers or tweezers. Be careful not to mangle the PTFE tubing sticking up from below. LOOK CAREFULLY before you start poking about or yanking on things.

If you can't reach it, and you have the proper tools available, do this:

If you got it, re-assemble everything in reverse order and carry on.

Re: Oh no! Problem ejecting filament

I’m sorry but I’m totally mystified here. I tried following some online directions for taking apart the extruder but it does not exactly match what I’m looking out here. I’m guessing that the design must’ve changed slightly after they created the documentation.

Regardless, the attached picture shows as far as I’ve gotten and I have no idea where I’m supposed to look for a blob of filament.

I hope to God I can get this thing back together.

Here is the link I was following for instructions:
https://manual.prusa3d.com/Guide/1.+Extruder+disassembly/220

Re: Oh no! Problem ejecting filament

Open up the extruder housing using the 2 screws on the left as viewed from the front. You may be able to see the filament sticking out of the PTFE tube below the extruder gears. Try to pull it out with needle-nose pliers or tweezers. Be careful not to mangle the PTFE tubing sticking up from below. LOOK CAREFULLY before you start poking about or yanking on things.

If you can't reach it, and you have the proper tools available, do this:

If you got it, re-assemble everything in reverse order and carry on.

Bobstro after about 20 hours of printing I started getting clogs with the provided silver PLA to the extent that I had problems removing the filament and heating and forcing filament through resulted in a too thin extrusion to be useful

the provided acupuncture needle was unhelpful (and given my age related essential tremor almost impossible 😉 )

I think the problem is in the teflon liner below the bondtech gears as it moves up to the gears during filliment removal due to the blob on the end I think this is due to the locking collet on the top of the cooling fined area not locking properly this means the the PTFE tube is not seating tightly on th top of the heat break .... Joan at some point posted some instructions on making sure that the tube was seated tightly against this part to prevent blob formatting that prevents removal of filament but I seem to have mislaid that bookmark the tube that came with my kit did not have the slight cone at the bottom as in the drawing for the part so it isteardown the hotted and extruder again and fit a new liner tube with a lock on the collet this time as the fix....

But I am sure Joan posted something about that fitting the tube to the heatbreak I guess I need to search some more

this does seem to be a weak point in the extruder/hotend design

Re: Oh no! Problem ejecting filament

[...] Bobstro after about 20 hours of printing I started getting clogs with the provided silver PLA to the extent that I had problems removing the filament and heating and forcing filament through resulted in a too thin extrusion to be usefulI was responding specifically to a problem with filament snapping off. I've used the method described to remove loose filament stuck below the extruder gears and above the hotend. I think what you're describing is a more specific problem with filament melting in the same general area. Simply pushing as I described may not be so helpful in that instance. I was able to remove a clog by pushing from above in this case but this is a different sort of blockage I think:

the provided acupuncture needle was unhelpful (and given my age related essential tremor almost impossible 😉 )While the needle might be helpful in some simple cases, I suspect most wind up lost or snapped off in the nozzle. After ordering some bits and trying to use them with smaller nozzle sizes, I've abandoned the "needle" idea completely.

I think the problem is in the teflon liner below the bondtech gears as it moves up to the gears during filliment removal due to the blob on the end I think this is due to the locking collet on the top of the cooling fined area not locking properly this means the the PTFE tube is not seating tightly on th top of the heat breakA lot of people seem to be having that issue, but it has never bothered me on my Mk3 delivered in April 2018. I don't know if there's any commonality in kit versus pre-build that might account for the difference. Unfortunately, a lot of other problems became common when we hit the high temps of summer, so there was a lot of noise around extrusion, heat-creep and jams. There seem to have been a few different problems that wound up under those headings.

.... Joan at some point posted some instructions on making sure that the tube was seated tightly against this part to prevent blob formatting that prevents removal of filament but I seem to have mislaid that bookmark the tube that came with my kit did not have the slight cone at the bottom as in the drawing for the part so it isteardown the hotted and extruder again and fit a new liner tube with a lock on the collet this time as the fix....I'm busily dumping everything I learn into my online notebook (see my sig below) but don't have anything helpful for you on this problem. Joan will be by shortly to sort you all out I'm sure.

this does seem to be a weak point in the extruder/hotend designGiven that so many people aren't having the problem (the sample size here is small given total Mk3 sales) I'm inclined to think it's an assembly/production issue rather than basic design fault. So far as I understand it, the parts in question are all E3D V6 parts that are widely used. There may be some difference in the locking mechanism, but I wouldn't say the problem is universal. Figuring out would definitely be useful.

Good luck with it!

Re: Oh no! Problem ejecting filament

I’m sorry but I’m totally mystified here. I tried following some online directions for taking apart the extruder but it does not exactly match what I’m looking out here. I’m guessing that the design must’ve changed slightly after they created the documentation. You linked to a beta manual that is, I think, outdated. I believe these are the current instructions.

Regardless, the attached picture shows as far as I’ve gotten and I have no idea where I’m supposed to look for a blob of filament. Well, you tore it down without trying the push-with-rod method I was suggesting to avoid doing so, so you're in for a bit more of an adventure. I can tell you that it all goes back together without too much fuss. Look at the current instructions, and just follow the process backwards. Go slow!

The blob of filament forms inside the metal finned gizmo (the hotend assembly) in the middle of all the parts you're holding. I think you went a bit beyond what's required. It'll be a good learning experience.

Re: Oh no! Problem ejecting filament

i second professor Honeydew's rob push method. it can save you allot of headache. only had to use once on my prusa. but on my poor wanhao many, many, times. but I abused the hell out of it.

Re: Oh no! Problem ejecting filament

Well, this is a comedy of errors. I heated up the nozzle and attempted to unscrew it with a 7 mm socket. To my great surprise, the nozzle broke off and the part of it with threads is still inside of the extruder housing, if that’s the right term for it.

I’ve attached a picture. I have absolutely no idea what to do now. Any suggestions would be much appreciated.

Re: Oh no! Problem ejecting filament

Oh man, that sucks. Slow down a bit and try contacting support. They'll be able to at least tell you what's needed to repair it. I think you just need the heater block if you can carefully unscrew and remove the heater cartridge and thermistor. These are very fragile, so don't attempt to do so without first confirming with support and very carefully following the instruction manual.

Re: Oh no! Problem ejecting filament

ouch, at least it should be a cheap fix.

Re: Oh no! Problem ejecting filament

I don't know if Prusa is assembling these or is buying them assembled from e3d but who ever assembles them should be using a high quality anti seize on the threads I had to apply way more toque even after heating to 250 for 15 min than I was comfortable with to remove the nozzle the first time. You can bet I hit the threads with this stuff when I installed the plated copper nozzle https://smile.amazon.com/dp/B0053ZS1Z8/ref=psdc_15719281_t1_B003THFRCC

I find these $6 or $7 stick type far less messy to deal with than the normal stuff in the can with the brush especially small things like the threads on a nozzle

Re: Oh no! Problem ejecting filament

Does anyone know how to get in touch with Prusa support? Last Friday, I tried emailing [email protected] as well as the contact email for forum support. I haven’t heard back from either account and there’s nothing obvious that I can find for contacting them on the main website, except for the sales email address.

One of the reasons I bought a Prusa instead of a couple CR10s had to do with Prusa’s excellent reputation for support. I just need to figure out how to contact them. Any help would be much appreciated!

Re: Oh no! Problem ejecting filament

Your best option is live chat which is on the bottom right of every shop page.

Re: Oh no! Problem ejecting filament

Does anyone know how to get in touch with Prusa support? If you need a quick response, you might try logging in and contacting Live Chat.

Re: Oh no! Problem ejecting filament

goto prusa Eshop then use that chat

Re: Oh no! Problem ejecting filament

The next time you want to change the nozzle, you first need to loosen the heating block a little bit before you get to the nozzle.

Re: Oh no! Problem ejecting filament

You may be able to unscrew the broken nozzle with something like this.
Never used it on a nozzle but it works good on normal screws:
https://www.amazon.com/Extractor-Aisxle-Stripped-Hardness-62-63hrc/dp/B01CA1PSCQ/ref=sr_1_1_sspa?ie=UTF8&qid=1540279427&sr=8-1-spons&keywords=screw+extractor&psc=1

Re: Oh no! Problem ejecting filament

hell just tap a flathead screwdriver with a hammer (lightly) a few times and see if you can unscrew. maybe even heat it up. then try that.

Re: Oh no! Problem ejecting filament

Thanks for the Locktite idea, Randolph! Just placed an order.

Unfortunately, this mishap was not covered by the warranty and I just ordered a new hot end assembly. Could’ve been worse, I suppose. Live and learn, right?

That Loctite anti-seize stick just might pay dividends. 🙂