Had an issue with one of my A1s repeatedly stopping extruding during prints, but in a way where the filament sensor is still triggered, preventing it from detecting the lack of flow and continuing to print despite no filament extruding.
After replacing basically the whole toolhead, it still keeps happening, and after some more investigation, it turns out a blob forms just above the hotend as shown in the picture above, that prevents the filament from moving down. I have tried with both PLA and PETG, and it keeps happening, along with filaments that work fine in my other A1 and mini.
I’ve put in a support request to Bambulab and they were zero help, telling me to clean the extruder and hotend despite the fact that I have literally replaced all the components with new ones. Does anyone know what is happening here?
A blob forming above the hot end is maybe too much heat for the filament along its path. If it’s an enclosed printer maybe too high of chamber temp? Heat creep?
It’s an A1, so not enclosed, and directly next to it, there is a second A1 that is printing with no issues. About the only thing I could imagine is if the extruder motor is getting hot too.
Somehow the filament is getting hot enough to deform before going into the extruder. My printer is enclosed and the advice is not to let the chamber get above 35C to prevent heat creep and those kinds of jams.
Maybe there’s air currents or the tubing goes by something warm, or maybe it’s an overheating extruder? But somehow the filament is getting warm enough by the time it starts to enter the extruder and deforming.
There’s not enough information in your posts to narrow anything down though. No room temperature or photos of your setup. You’ll need to search for any hot spots and take the temperature of your extruders to narrow things down.
With the PETG its running at 220c and PLA its currently set for 250. I don’t have a thermometer so can’t tell you the temperature but there is a second A1 next to it running fine, as you can see in the pictures.
I think[hope] you meant that in reverse else, 250 seems very hot for PLA and I would expect other issues, not just creep.
Looks like an outdoor-ish unconditioned space, it’s summer here. How hot? Your machine shoudl tell you roughly the ambient temp when you walk up to it and see the cold nozzle/bed temp. 40+ would be my danger zone for open air PLA but admittedly theres lots of variables here
Yes, got those temperatures the wrong way around. Its below 30c within the space based on the rough ambient temperature. At this point, the only part in the toolhead that hasn’t been changed is the casing itself, everything else has been changed.
Just checking on it now, same thing has happened, the only difference between it and the printer next to it is it’s toolhead is noticeably hotter on the issue printer than the other one. Not really sure what could cause that though.
Those are temperature regulated, I believe. There should be a temperature sensor in there too to close that loop.
If the sensor isn’t well coupled thermally to what the heater is heating, it could be the heater is being commended hotter than normal so the temperature sensor can read normal.
Not sure if that’s clear but maybe the temperature sensor is loose or missing thermal compound (if used).
else, 250 seems very hot for PLA and I would expect other issues, not just creep.