0.25mm Nozzle Clogging - Heat Creep?
Hello everyone, today I had a print go about as bad as it possibly could, so I'd like to share and ask for some tips to avoid this in the future.
I was printing a mechanical part for which I needed very fine details, so I went with the 0.25mm nozzle (an original Prusa brass nozzle) and used the Prusament Natural ASA material. At some point it must've clogged the nozzle, but no fault was detected and the print just continued until much later when I noticed weird noises and no plastic coming out.
A simple clog would be fine-ish, but melted plastic got all the way up behind the planetary gearbox partially melting the "extruder main plate" which got pulled into the gears, seizing the whole mechanism. As a bonus, once I took apart the gearbox, I saw a bunch of plastic had accumulated on the heatsink, so I started cleaning and...... turns out that was the load cell's sealant, not the filament 🙃 and, of course, I totally annihilated the sensor turning what would've been a cheap replacement into a lot more. If only I was printing any other color, it'd be obvious...
That last part is just me being dumb, but the awful clog ... doesn't feel like user error - was it?
- How do I avoid clogs with the 0.25mm nozzle? I already made sure to use a fresh, dry filament without any particles in it, purged a lot before printing. Slicer, its presets and printer FW are all up to date, nozzle configuration was correctly set also both on the printer and in the slicer. Is ASA just a bad combo with smaller diameter nozzles?
- Don't Prusa printers detect e.g. the extruder motor skipping, or any other sort of clog / stuck filament indication?
- Why is the "extruder main plate" part PETG? Most of the Core One plastic parts used within its chamber seem to be PC CF, yet this one, so close to the hottest bits of the printer, is made of a material softening at 85C? Weird...
Thanks for any tips and happy printing!