I recently had a very nasty problem with my extruder.
Some hickup caused the start of the print to fail, the printer went on halt but the hotend stayed on.
Fixed the issue, started the print again and got to hear the cutter is stuck…
I was calibrating some glow in the dark filament.
Knowing the stuff is like sandpaper is one thing but that our hotends struggle this badly to prevent heat creep…
So what happened ?
After checking everything it became obvious I had the hotend full and the top fully blocked up.
The filament got so soft that the extruder caused it to fill up the entire hole like a plug.
No big deal, blowtorch, wire and a good pull.
Then the extruder still failed to transport things, neither forward, nor back.
The filament cutter made the final cut when the plastic was already squished out badly.
Either the cut was not complete or due to getting stuck in the hot plastic it all deformed a bit.
Now I had a plug between the outlet of the extruder and where the filament goes in.
Yes, this tiny gap where the two wheels move it along…
I could wiggle it back and forth a tiny bit …
Had to drill it out in order to get enough movement to pry the extruder wheel past this filament blob…
It’s quite cold here right now, so I usually don’t leave the door open.
Never had a problem with this even on a hot day.
Time to check this filled filament and those new rolls of copper filled PLA…
After heating up some solid test cubes the first issue was obvious.
Glow PLA and metal filled PLA hold heat far longer than normal PLA.
The beauty of FLIR cameras is that you won’t need a contact sensor that might mess things up.
The second issue wasn’t that obvious…
Once PLA gets cold it shrinks quite a bit.
Ok, not like ABS and such but still.
Glow PLA and the copper filled one I tried however show little to no shrinkage when melted into a mould.
For our hotend it means that once certain filaments got too hot and filled the cold end of our hotend stopping all extrusions can be fatal.
I would be nice to have a button for such filaments to do a flush with a different filament once a print is done…
I now print those filaments much slower than what I could but also use a much lower nozzle temp.
This way I won’t risk having the hotend, or worse, the extruder blocked again.