Now I can insert this from the bottom into the hole, to remove partial blockings.

So you have to reshape the M3 rod on a grinding disk, and then cut big cutting-paths in it (I dont' know the correct name) with a thin nylon cutting disk on a Dremel, so it can bite into the PVA and remove the loose debris.Īlso, for cleaning the nozzle tip (=0.4mm on my UM2), I have modified a thin injection needle: I cut off the sharp tip and round the edges. But that probably won't work for you, since you need a sharp tip to cut through the PVA from the top, not the side. It scrapes the sides like a soft file, sort of. I sometimes use a brass M3 rod to clean the side-walls of a nozzle, if there is too much dirt accumulated. (Maybe this would be a good tool to provide standardly with all printers?) So your custom drill should be softer than the nozzle-internals, but harder than the plastic you want to remove. Ideally, give the tip of your self-made drill the same shape as the internals of the nozzle-tip. If regular cleaning would fail, and you are going to drill out the nozzle anyway: maybe consider making your own drill from a 3mm copper or brass rod, or a brass M3 threaded rod? Brass is less hard than steel drills, and thus far less likely to damage the nozzle internally. Some of the methods above would obviously void any kind of warranty, etc. This is all my own speculation, and I'm not someone focused on materials. WARNING, drilling is likely to damage the PTFE insert or the metal of the hotend as much as the plastic stuck in the printcore. Get a small drill bit (preferably used manually) to drill out the filament until you can perform hot/cold pulls. WARNING: water and electronics do not mix, be very careful!!!! by pouring a smal amount into the top of the hotend, circulation would be a huge problem though, will likely take multiple attempts. (I've used air pressure before to get a clog out, it did work but does not clean much but the clog itself) also air pressure may make things fly, take the appropriate precautions. WARNING: if any hot plastic makes it past the PTFE insert and sticks to the metal there it's even more difficult to remove. Use air pressure to push the filament out the other way while the hotend is hot. You can try pushing it out while it's extra hot That said I do have some guesses that might work: I've not encountered the situation that a hot pull did not work at all, That does make me wonder if you are doing the hot pull corrctly it is very short not more than a second all the way inside the printcore.

Ultimaker 3 hot pull