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Difficulty loading filament - MK3S  

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leo.c5
(@leo-c5)
New Member
Difficulty loading filament - MK3S

I seem to be having trouble loading new filament when the old spool runs out. I'ts happened 3 times now, each time when the filament runs out and the trigger activates as it should, the old filament is pushed down in to the extruder just out of reach of the gear. When new filament is loaded, it can't seem to push the old filament down. 

Each time the only solution I've found is to up the nozzle temp and use a thin hex wrench to push the old filament down enough that the new one can fit in the PTFE tube and catch the gear.

Surely I must be missing something, the old standard MK3 had no issues doing this but since the upgrade to MK3S happens all the time .

Posted : 14/11/2019 11:18 pm
JoanTabb
(@joantabb)
Veteran Member Moderator
RE: Difficulty loading filament - MK3S

the printer is supposed to spit the stump of the old filament back out. 

it should never get as low as the bondtech gears on a Mk3S. 

If your old filament is getting down to the bondtech gears, there may be a problem with your filament sensor, or it might be turned off...  

heat your printer tot he correct temperature and remove the filament. 

cut the end of the filament as recommended for insertion and push it into the top of the extruder, If the filament sensor is enabled and Autoload is enabled, the filament sensor should see the filament being inserted, and activate the extruder motor to load the filament. 

if this does not happen, remove the filament, change the LCD to display the Filament sensor status. then observe the display whilst you push the filament into the extruder and remove it... the sensor status should toggle between 0 and 1   where 1 is filament inserted and 0 is filament out...
If this is not working, try and sort it out then try again... 

 if the end of the old filament is tightly curved.  then as it passes into the top of the extruder, and is sensed by the filament sensor, the end if the filament can catch on the inside of the extruder housing and prevent ejection... 

this is particularly bad, if the end of the filament was bent through a hole on the roll, when it was wound... 

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

Posted : 14/11/2019 11:36 pm
leo.c5
(@leo-c5)
New Member
Topic starter answered:
RE: Difficulty loading filament - MK3S

@joantabb

Thank you so much for your reply but I'm still having the problem. The filament sensor is turned on as is autoload, and it activates when filament runs out but happens too late. This causes the bondtech gears to push the filament down too far for filament to unload properly, so when I run the unload command the gears spin without the stub releasing. 

I did as you suggested and tested the sensor, it triggers correctly between 0 and 1 when filament is inserted/removed, and I can feel the sensor itself moving so I know it's working correctly, just seems slow. 

Really not sure what to do here... should I open a ticket with Prusa support?

Posted : 24/11/2019 12:13 am
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