I know this is somewhat of a common topic but I am seriously out of ideas of what to try here. So I accidentally printed a miniature using PLA but I forgot the printer was set to ABS settings. Obviously this didnt work. The PLA was acting like it was stuck in the extruder and I had to work pretty hard to get it removed. The issue now is that I cannot load new filament of any kind. I have tried loading ABS and PLA and it is not working. It feels like something is stuck about half way down into the extruder. I have tried to force it through by putting in new filament and having it push it through. This down not work. I have tried upping the temperature as some people suggested this also does not work. I tried using the spike tool in the kit to push it through myself also doesn’t work. I cannot see the jam when I look through the hole in the extruder so it must be further down. One person said to try turning off the cooling fan and heat it up which did not solve the issue either. I am completely out of ideas on what to do at this point. The only thing I haven’t tried is disassembling the whole thing which would void the warranty I bet so I have not taken this step. I have emailed lulzbot support and I am getting the same advice I looked up online which is not working. I finally took a video and sent that to support. I am receiving a response at best every two weeks after submitting a question. I try to be a very understanding person but I have to admit I am getting pretty upset at the fact I paid over a thousand dollars for this thing and its been sitting not operable for weeks and I am not really getting any help with it through the proper channels. Hope someone out there has something new I can try so I can use this thing.
The extruder has both a “hot end” and a “cold end”. These are separated by a gap called the “heat brake”. You’ll see the upper part of the extruder … the block with the heat-sink on the side and the cooling fan. Then below that you’ll see a narrow gap … then below that is the block that holds the extruder (this is the “hot end”.)
Normally only the hot end gets hot… heat tries to migrate up into the cold end, but there is that narrow gap called the “heat brake” so that the hat and cold sides don’t have a lot of metal touching each other (making it harder for the heat to migrate) and the upper side has the cooling fan on the heat sink to keep it cool).
IF the upper part gets hot, then filament can melt in there and that would create a jam that wont get cleared by raising the temperature of the printer. Disconnecting the cooling fan and letting the printer warm up a few minutes allows heat to deliberately migrate to the cold end in the hope that it will melt filament and get things flowing again.
If allowing the “cold” end to get hot doesn’t clear the jam, then you might need to remove the nozzle to try to clean out the extruder.
There’s a good YouTube video with instructions: https://youtu.be/rjMqF6xGb28
It is unlikely that you’d need to remove the print-head … but if you do (or are trying to get access to the top side of the extruder and want to do a partial disassembly) here are the instructions for how the printhead is assembled:
The print head probably does not need to be removed from the printer, but it can be removed… it is a modular head and designed so you can easily swap out this head with an alternate head. The heads have a modular wiring harness that would be disconnected, the cosmetic cover on the top is removed, and then there are three screws that attach the print-head to the X-axis carriage.
Use a flashlight and look down the hole where you push the filament. If you worked it around a bit while pulling the old filament, you may have misaligned things.
Mine has a distinct ledge down there and I often cut my filament with side cutters to create an edge that helps guide it past the ledge. It also helps to straighten the new filament to get rid of the inherent curve.
If you can’t get new PLA filament pushed through the nozzle on say 220 to 250, you may have a crystallized chunk that won’t go through the nozzle.
The nozzle isn’t that hard to remove. You just have to establish an understanding of what to turn and when. Think of the heater block as a “jam nut” for the nozzle. All the stuff has to be hot while you’re doing this. Because different metals expand/contract at different rates.
Good luck, and I’m glad I got to learn my machine while Lulzbot had good service. I had questions answered via email in minutes, and often on weekends. Apparently they need to bring back good customer service.