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MK2 - PETG is plugging the nozzle 🙁  

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Bastian
(@bastian-2)
Trusted Member
MK2 - PETG is plugging the nozzle 🙁

Hi there,

i'm frustrated -.- I'm using a MK2 and actually (= since 1 week), i'm trying to print the parts for the MK2S and MK2.5-upgrade.
My actual problem is, that the PET, that's shipped with the two upgrades is plugging my nozzle, so that no filament left's it.

I tried a hot- and cold-pull, also i tried to clean the nozzle with the little needle shipped with the printer. After the cold pull, the pulled out filament seemed very clean and i thought, i got any clogs out.

Then i started a print and on 3,6-3,8 Z-Height, the printer stops to transport filament trough the extruder. Normaly, i hear the extruder-motor, when the filament "slips through" (as you can hear in the following video). I'm not sure were's the problem - the print before this try had the exact same problem in the same Z-height ?!

[youtube] [/youtube]

The last 10-20 prints where in ABS, then i switched to the PET from Prusa; i set the printer to ~230-240°C on the filament change.

Is there anything further i can do to clean the nozzle?

Postato : 10/06/2018 12:47 am
rob.l6
(@rob-l6)
Honorable Member
Re: MK2 - PETG is plugging the nozzle 🙁

How old is the nozzle? If it's getting on a bit you may as well replace it. It would be easier (and quicker) in the long run.

Postato : 10/06/2018 6:58 am
Bastian
(@bastian-2)
Trusted Member
Topic starter answered:
Re: MK2 - PETG is plugging the nozzle 🙁

Hey Rob,

the printer (and the nozzle) is 2,5 years old. I didn't print as much as others, so i think round about 100 hours? I think, round about 2-3 1kg filament spools run through the nozzle.
I recognize, that this two printer updates will take some time (and are not done on one weekend), so if it's a good idea, to replace the nozzle time by time, then i will order one.
Because of the last failed prints the PET from Prusa will not be enough to print all upgrade parts, so i have to order a new, full spool - so i can order a new nozzle in this step too.

Till this part is shipped, are there other options to clean it? If i clog is blocking the end of the nozzle, i will try to remove it again with the needle while i'm pushing filament through the hotend and try my printjob again.

Thanks for your help!

Postato : 10/06/2018 9:48 am
rob.l6
(@rob-l6)
Honorable Member
Re: MK2 - PETG is plugging the nozzle 🙁

Yes, certainly order a few nozzles, even the cheap J-head brand (for example) are fine.

In the meantime check out Tom's guide and vid on cleaning, including removing the nozzle to clean. It may help.

https://toms3d.org/2017/01/09/basics-cleaning-clogged-nozzle/

Good luck.

Postato : 10/06/2018 10:09 am
Bastian
(@bastian-2)
Trusted Member
Topic starter answered:
Re: MK2 - PETG is plugging the nozzle 🙁

Hello rob,

thanks for the info's.
I ordered a bunch of new J-Tech-Nozzles and cleaned the nozzle again (cold pull). Actual, i give my last failed print a third try.

As i have to disassamble the printer to upgrade to MK2S and MK2.5 - do you have any suggestions, what i should replace or maintain, that is not described in the assembly instructions? I remember, that there's a PTFE-Tube inside of the extruder that can causes problems, when printing ABS and could be a cause for a clogged nozzle too; so would it be a good idea to replace it?

Thanks in advance!

Postato : 10/06/2018 10:48 am
Bastian
(@bastian-2)
Trusted Member
Topic starter answered:
Re: MK2 - PETG is plugging the nozzle 🙁

Short Update: I switched after another failed print with the original 100gr PET from Prusa to a new spool of cheap Sunlu PETG and till now, i have none of the previous problems. Also, the print seems to be clearer (top layers and infill).

I'm sure, that the 100gr PET from Prusa was correctly boxed (no air in the plastic foil, ehrm, i mean, compressed?). So... bad filament spool?

I will replace the nozzle, assemble the MK2.5-upgrade and check the Prusa PET again for some prints...

Postato : 10/06/2018 12:31 pm
rob.l6
(@rob-l6)
Honorable Member
Re: MK2 - PETG is plugging the nozzle 🙁

Quite odd, but perhaps there was still a tiny clog that was inadvertently cleared with your last print.

The modern wonders of consumer FDM printing 😉

As to your other query I think there are some quite helpful posts already in the Mk2.5 group.

Postato : 10/06/2018 12:47 pm
Bastian
(@bastian-2)
Trusted Member
Topic starter answered:
Re: MK2 - PETG is plugging the nozzle 🙁

Hey rob, i've new info's - maybe.
I tried a last time a cold pull, because i got a clogged nozzle after ~20 Minutes of print with the cheap Sunlu-Filament. I don't think that i got anything out of the nozzle, that was left over from the previous tries - the top of the pulled out filament seemed exactly the same as the cold plugs (also with the prusa petg) before.

Then, i dont know why, on the next print i did something different than before: My printer is in an ikea enclosure and i left the door opened. The print completed without any errors. With the door closed, i got about 40-45 degrees inside - with the door opened, round about 30-33°.

Then i searched a little bit - i don't think, that this is the cause, but also i don't think, that there are clogs in the nozzle left, that caused the jam: Maybe, with ~45° inside of my enclosure, the PETG get's to hot and begins to melt (or: it get's a little bit softer), so that the extruder gear can't push it further into the hotend. After 1-x minutes with no filament movement, it form's a clog inside the hotend which causes a jam.

With this in mind, i started an 12 hour print before i go to work. And, god damnit, the print succeeded without any clog or problem!

I will start a bigger print over night, the last parts before i assemble the mk2.5-upgrade:
https://www.thingiverse.com/thing:2836470
I'm exicted - i will give you a update, how the print was going :->

Postato : 11/06/2018 8:10 pm
rob.l6
(@rob-l6)
Honorable Member
Re: MK2 - PETG is plugging the nozzle 🙁

💡 Always remember to go back to "default" settings (in your case eliminate the enclosure) when trying to diagnose a problem.

But it sounds like you have found the cause now. 🙂

Postato : 12/06/2018 5:32 am
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