Can't get extruder apart
I was trying out multi filament printing for the first time and it was going well until I started getting filament load errors. I cleared a few but eventually it wouldn't continue. It seems that the PTFE tube is completely bunged up so I thought, OK, I'll just remove the hot end and replace the PTFE tube. The problem is I can't get the extruder assembly apart. The long screw on the left just below the stepper motor wouldn't unscrew. I applied a bit more force and just managed to spin the nut in the plastic. I've tried melting some plastic around the nut so I can get some needle pliers in to hold the nut but still can't get the screw to undo. I can only assume that the screw thread is damaged and is jamming in the nut (I can unscrew a couple of turns and then it jams). Any ideas?
I can see that I'm going to destroy the rear plate to get it apart, but then I can't print a new one (catch 22). Help!
RE: Can't get extruder apart
Hi Rod,
If the printer is still assembled, try heating the hot end as far as it will go 295C I think, then while it is heating, remove the Bondtech door tensioning screw, and use a 1.5mm allen key to push through the filament path from the top down.
if this doesn't move the blockage try removing the nozzle, and then re apply the allen key whilst the hot end is still hot
regards Joan
I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility. Location Halifax UK
RE: Can't get extruder apart
@joantabb
Thanks for the reply Joan. I did try heating it to 260C without success. Its in bits at the moment but I guess I could reassemble and try again at 295C. At least I'd be able to print a new extruder body before I destroy the existing one.
Rod
RE: Can't get extruder apart
Reassembled and heated to 295C but still couldn't push through with a 1.5mm allen key. However, had a poke around at the top of the PTFE tube and managed to free a conical shaped plug in the chamfered end of the PTFE tube that was clearly stopping filament from loading. Anyone seen this before? What causes it and what can be done to prevent it?
I still want to replace the PTFE tube but at least I should be able to print replacement extruder parts so it doesn't matter if I destroy the existing ones.
RE: Can't get extruder apart
Hi Rod,
I have heard reports, that, If your printer gets too hot, perhaps, the combination of high ambient temperature and heat from the
extruder motor shaft combine to soften the PLA above the PTFE. and then the bondtech gears carry on feeding soft filament into the top of the PTFE, which is tapered, the filament expands and this causes a block above the PTFE
this also happens if the printer is in an enclosure and the enclosure temperature gets too hot...
I have never had it happen to me, but I live in Chilly england...
regards Joan
I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility. Location Halifax UK
RE: Can't get extruder apart
@joantabb
Hmm, sounds plausible but I live in chilly England too 🙂
My current theory is that the IR sensor was not behaving itself and the gears forced too much filament into the PTFE. I have experienced blobs under the nozzle from time to time too which could be indicative of the same problem. I'll try recalibrating the IR.
Rod