Filament break, can't unload
Hi, I've been having a relatively trouble free experience with my fully assembled i3 mk2. Till now. Recently, I've mostly been printing with copperfill as I'm doing an art project.
Problem 1: I've had a couple prints occur in which the printer stopped mid-way for no apparent reason. I figured that my USB cable was too long (I extended it to 15ft or so), so I started printing over night prints with the SD card only.
But, even with just the SD card, I had a print stop printing mid-way, with the head moving to the end position (where it goes after a print), but with the heat still on.
Problem 2: This last time, I appear to have developed a clog too. As when I restarted the print, no filament comes out at all. I figured that I should unload the filament and try to clear the clog with the needle that came with the printer.
Problem 3: The filament would not unload. The motor turns, but the filament didn't come out. So, I pulled on the filament, and it broke off at the hobb gear. Copperfill is brittle, and I got a little too forceful with it. There's just a bit of it visible above the opening into the remainder of the extruder, but I can't grab is with needle nose. See the attached photo
I bought this printer as a fully assembled. And, while I'm pretty mechanically inclined, I'm worried that I'll screw something up and break my printer.
How can I get that filament out with the least dis-assembly?
I'm thinking I could loosen the hobb screw and push it further onto the stepper motor shaft. That might allow me to grab the filament end with needle nose. If that doesn't work, then what?
Looks like I'd have to remove the extruder completely and take the hobb motor off.
Assuming I can get the filament out, for problem 2, how do I unclog it? Are there instructions on how to do that (I didn't find any).
Then if I can get it all unclogged and back together, problem #1, what is causing the prints to stop?
Re: Filament break, can't unload
Did you try it the other way round? Instead of trying to pull it out, try to push it down and out though the nozzle.
Leave the extuder door open as it is now. Preheat the nozzle for a few minutes to PLA temps (copperfiill is PLA based, right?), then try to push down on the remaining filament. A allen key small enough to fit into the PTFE tube comes in handy for this. Once the blockage is lose, it is usually enough to use filament to push it all the way. You could also try to losen up the blockage if you poke from the nozzle up using either an acupuncture needle (Prusa shipped one or more with the printer) or another good tool is (uncoated) guitar strings.
If this isn't working, try this:
users on the forum reported good success when disconnecting or removing the hotend fan to losen up clogs in the cooler parts of the extruder / above the heatbreak, as heat will be creeping upwards and soften filament stuck there. I haven't tried it myself but the idea sounds good.
If that still wont work, i guess it's time to disassemble the hotend.
As to why you're having these problems with prints stopping mid way, I don't know. There used to be a problem with saving files on older versions of Slic3r, but i was told the problem has long since been fixed. I had it happen to me once and i am not even using Slic3r, so there seem to be other factors involved besides that old Slic3r bug.
Re: Filament break, can't unload
And do not use abrasive filaments with the standard nozzle.
You need to use a hardened/stainless nozzle when printing copper/brass/carbon/etc.
You will probably find you nozzle is damaged and any damage can cause clogging.
Peter
Please note: I do not have any affiliation with Prusa Research. Any advices given are offered in good faith. It is your responsibility to ensure that by following my advice you do not suffer or cause injury, damage…
Re: Filament break, can't unload
I heated up the extruder and poked the needle up. It hits some kind of blockage around 20mm up into the nozzle. I can't push the end of the filament down at all.
So, no success yet, but I'm about the remove the fan to see if I can get the heat up the pipe a bit further.
Where would I buy replacement nozzles, like the stainless one mentioned.
Also, where do I buy any replacement parts. The Prusa web site lists 10 replacement parts available, but no nozzles in stock or anything extruder like. Really not much in the way of parts at all.
Seems like I should be able to build up a second extruder assembly and swap it out when needed. I haven't looked for the files, but am wondering about the non-printable parts.
Thanks,
John
Re: Filament break, can't unload
The hotend used in the MK2(S) is a "original E3D V6 Universal 12V". Hotend, spare parts and nozzles are available from the hot end manufacturer, like here: http://e3d-online.com/E3D-v6/Full-Kit/v6-1.75mm-Universal or their various resellers world wide.
There is a hidden spare parts section in the Prusa shop. Log in with the account you purchased your printer, then use the chat feature and ask for access to the hidden spare parts section.
Re: Filament break, can't unload
What was the outcome of this? I have a similar issue.
Thanks, David
Re: Filament break, can't unload
You're not gonna like this but...Had it happen to me also. Just could not get the bugger out. I took off the nozzle and used one of the allen keys that just barely fit and medium sized screwdriver's handle to just thump it out. Took a few hits but it eventually worked.
Neal