Printer jamming when unloading filament
I've had my MK3 for around 12 months and all has been fine until a couple of weeks ago when I stared getting problems with filament unloads. The prints themselves look great, but when I do a filament unload it more often than not it sticks. It also seems, the longer the print, the harder it it is to eject (pull) the filament.
Stats say I've run about 1400 meters of filament and about 500 hours but i have also starting running prints throught octoprint which i understand dont get included in these stats, so these figures could be low.
I mostly run PLA, but occasionally PETG.
I've tried a cold pull per the prusa instructions and everything looked fine and I regularly run cleaning filament through the extruder.
Can anyone offer any advice as to what may be going on? I've just run a 6 hour print that involved a colour change after 5 hours, the filament stuck when unloading and when i did manage to get it out and the new colour in, the extruder was creaking like mad and eventually stopped extruding.
Any help would be greatly appreciated
RE: Printer jamming when unloading filament
Hi Pete, where are you located?
Are you printing PLA?
Are you using an enclosure?
what retraction length are you using?
What do your filament tips look like? are they swollen?
excess retraction can cause this sort of problem say 1mm or more I generally use 0.4mm
High ambient temperature can cause this sort of problem If I have my solid fuel fire on, I have this sort of problem. (Has summer just arrived in your area? That can cause higher temperatures, too)
Printing PLA in an enclosure often causes this sort of a problem,
Partial blockages of the nozzle can cause this sort of a problem,
LOTS OF RETRACTIONS can cause this sort of a problem
Filament waste between the heat block and the heatsink, can Cause this sort of problem (this often occurs after a Blob of doom, if the gap between the heater block and the heatsink s not cleaned well, or is filament leaks after a nozzle change, or if the nozzle / heatbreak are not assembled properly (this can also occur if say a Mk8 extruder nozzle is used in a prusa printer instead of an e3dV6 nozzle)
there are other possible causes, but these are the main ones.
Good luck...
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: Printer jamming when unloading filament
Hi Joan, thanks for the reply. I'm In South wales,
I'm using mainly pla with the occasional petg,it is in an enclosure but the temperature doesn't go above 30 and I also get the problem when the doors are left open. Retraction is set to the default. I did have it set to 1.2 at one point but reset to the default when I started to get the Problem, I haven't changed the nozzle, its the one that came installed with the kit, but I have just ordered some new ones.
I do see a blob on the end of the filament when I can finally get it removed.
RE: Printer jamming when unloading filament
30C seems high for PLA
maybe changing the nozzle will reduce back pressure and stop the filament swelling
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