Severe snap/clog Lulzbot Mini

So I’m still relatively new to the Lulzbot Mini, but for a while things have been going well. Last night I set up a long print - one of the longest I’ve ever attempted (6+ hours) and went to bed. This morning I found that the print malfunctioned early in the run, and tried to print for those 6 plus hours and nothing came out. I tried to remove the filament (with a ton of force, as always) and discovered that the gear that feeds the filament had chewed its way through, and my forceful tug snapped the filament right at the weak chewed up point.

Now I’m stuck with a nub right at the gear that won’t budge. I can’t pull it out or push it through. I’ve tried superheating the printer (I’m using PLA and pushed it to 250) and while some filament did dribble out, the trapped filament still won’t budge.

Is there anything I can do, or is this whole thing busted? Any help would be appreciated.

Use one of the small allen wrench that came with the printer, probably a 2.5mm, 2mm or 1.5mm and while the hotend is heated plunge it down into the nozzle to push the heated filament through

Yea you can use a tool to try to push it. Also you can go to 300 with that hotend just don’t go over that.

If you plan on doing PLA often, look for any of the fan mods on Thingiverse. That little fan included does not cool the heatbreak down enough for PLA and it suffers from what is called Heat Creep (you can also search for that on this forum). it’s when on longer prints the heat break gets hot enough to melt PLA and it gets stuck higher up than it should. ABS does not have the same issue but a bigger fan is still a wise and cheap upgrade.

As a last resort, you can remove the extruder body to grasp the remaining filament. Its held together by 2 M4 screws, one of which may be obscured by the fan. You may need to figure out someway to heat up the hotend (while dissassembled) so the filament can be removed…

To be honest, I’m guessing the root cause of the print failure was heat creep up the hotend. Its also possible the heatsink fan failed. If the filament has melted in the chamber, it could take some disassembly of the hotend to salvage. Basically, remove the heater block and soak the heatsink in SCIGRIP solvent to dissolve the PLA… the exact solvent is mentioned in the forums, search “SCIGRIP”… it could be nopick that suggested the solvent…

Keep us posted… always good to hear outcomes.

Yep. SCIGRIP 4 does the trick. I have probably saved $100 worth of nozzles with that $10 can.

I drop the nozzles right in the can and leave them overnight.

SCIGRIP 4 10308 Acrylic Solvent Cement, Water-thin, 1/4 Pint Can with Screw-on Cap, Clear

Do you have a name for or link to the specific fan upgrade that you mentioned. I looked on Thingiverse and didn’t find anything.

Might have to modify mine to fit the mini (made it for the TAZ 4 with Hexagon upgrade) but here it is