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Hot end jammed  

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mike.w12
(@mike-w12)
New Member
Hot end jammed

I was trying to print with a new nozzle, 0.2 mm, Prusa grey PLA, 210 deg. I sliced my model in slic3r (latest version) and the only change I made in comparison to my normal settings was the nozzle diameter. The first time I tried I got a jam very early. Strangely, the printer didn't detect this. It just started making a clicking noise and no plastic was coming out the bottom. I would have expected the optical sensor should have seen that no plastic was going through and stopped it. Anyway I stopped it myself and then I was able clear it the jam pretty easily by just pulling out the filament and fiddling with it. So, I figured maybe that was a fluke and tried again.

This time I foolishly went to bed. When I came down in the morning the print had finished, but only the first half of the result had printed. Now the hot end is really jammed good. I removed the filament, then removed the nozzle. Then heated it up to 280 and tried using a small (1.5 mm) hex key to dislodge the jam from below. I have been unsuccessful.

My first question (obviously) is does anyone have good advice on how to clear the hot end? I have read about/considered totally dissembling it. After I do that can I heat it up to help clear the plastic inside? Is there a guide I should follow.

My second question is, when I get it up and running again, what can I do to not get the jam again. Do I need to change settings other than the nozzle diameter in Slic3r? Is it possible the cheep nozzle I got from Amazon is just not going to work?

Thanks for your help in advance.

Posted : 04/08/2018 8:50 pm
bobstro
(@bobstro)
Illustrious Member
Re: Hot end jammed

I've previously pushed with the wrench from below to get unmelted broken filament stuck below the gears but above the hot end out. It sounds like you've got molten material partway down into the PTFE tube above the hot end. Before you go tearing too much apart, read through this thread. There's some good info in there if you read from the top, but you might want to take a look at my adventures with a plug at the end. A 1.5mm brass rod, smoothed and rounded at the ends, was sufficient to drop through the loosened extruder gears into the PTFE tube and push a block out. Be careful that you don't knick or distort the PTFE tubing. Worst case, you might end up tearing it all down and going a PTFE tube replacement.

I have not had good luck using the cheap brass 0.20mm nozzles. A genuine E3D plated copper 0.25mm nozzle and larger cheap brass 0.30mm nozzles work fine. More discussion in this thread might be useful.

My notes and disclaimers on 3D printing

and miscellaneous other tech projects
He is intelligent, but not experienced. His pattern indicates two dimensional thinking. -- Spock in Star Trek: The Wrath of Khan

Posted : 04/08/2018 11:34 pm
RH_Dreambox
(@rh_dreambox)
Prominent Member
Re: Hot end jammed

https://help.prusa3d.com/l/en/category/A6PvLnaCoU-maintenance

Bear MK3 with Bondtech extruder

Posted : 05/08/2018 9:54 am
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