Clogged extruder after 13+ hours of printing - using PLA
While clogs are nothing new in the 3D printing world, this would be my first one since getting my MK3 in June. This was by far the largest print I've ever attempted. It had gone around 12 hours before I went to bed and everything was looking great. I came downstairs in the morning and it's printing air about 2 1/2 inches above the top of the print.
Firmware: 3.2.1
Filament: Atomic PLA @210c
Slic3r profile: using the Prusa PLA as the baseline with slight modification
Here's what I've tried so far:
- Heat up the nozzle, unload the filament, and stick the acupuncture needle into the nozzle. The filament unloaded fine with a bit of resistance. Not sure if a blob may have broken off the end.
- I tried to reload/unload a few times.
- Initially I was getting some extrusion, though not completely.
- I tried unscrewing the idler gears and then manually fed filament with the temp at 250c. It came out, but wanted to hug the side of the nozzle and curl up rather than coming out straight.
- Last night I ran the self test to make sure the extruder fan works... all checked out.
At that point I gave up for the night. I attempted again the next day and now nothing will come out of the nozzle, so it's a mess. The nozzle itself appears to be mostly clear, so the blockage is further up into the extruder body.
In some of the instructions on the Prusa site (or in the 3d printing manual) it mentions getting a wire that is 1.5mm diameter and after heating up to 250, try pushing in from the top to force stuck filament out of the nozzle. I haven't yet tried this, but am considering it. I've also read about the "cold pull" method.
Any advice for a 3d printing newbie?
Re: Clogged extruder after 13+ hours of printing - using PLA
So I decided to disassemble the extruded body to get at the clog. As I suspected, it was in the heat break. I took the nozzle off, heated the hot end and then used a wire to push out the blob of filament. Unfortunately, I think I got some goop on the threads for the nozzle. When I went to replace the nozzle, I only got within 3-4mm of having it tightened, but it won’t go any further. Any suggestions?
Re: Clogged extruder after 13+ hours of printing - using PLA
The nozzle does not tighten down flush with the hot end. Do not crank it down! Refer to the manual. Brace the heater block with a 16mm wrench while tightening or you may snap the heartbreak.
Re: Clogged extruder after 13+ hours of printing - using PLA
Thanks for pointing that out. 
I did follow the manual instructions for removal, but when I went to put it back on, it looked like it was sticking out too far.
On another note, when I was disassembling, I noticed that the heat sink was loose. I’m wondering if that contributed to the clog.
Re: Clogged extruder after 13+ hours of printing - using PLA
On another note, when I was disassembling, I noticed that the heat sink was loose. I’m wondering if that contributed to the clog.
Yes ! there will be heat creep if the heat break is not firmly in contact with the heat sink. I had to add thermal paste to get rid of the issue