Overheated extruder motor melting filament
Greetings,
I have build 5 prusa i3 MK3's last week (for the university of Antwerp).
And there is one specific issue i start noticing on all 5 of them. Some are more affected then others but i have not spotted the reason.
When the printer prints a part the extruder motor heats up. I have read this is normal and allowed up to temperatures of about 75°C.
That i get since these are decent motors. But the problem i have is that this heat is transferred trough the shaft up to the extruder wheel and into the filament.
If i wait for 10min between prints (yes, i have a print waitline) this heat has gotten into the filament whereby this has melted. When the printer then starts this jams up the opening on top of the ptfe tube of the hotend.
I notice i am not the only one with these problems, although not al off them realise this could be becouse of the heat yet it seems:
https://shop.prusa3d.com/forum/hardware-firmware-and-software-help-f64/filament-jam-t15506.html
https://shop.prusa3d.com/forum/hardware-firmware-and-software-help-f64/filament-continually-clogging-and-getting-stuck-in-t15620.html
But my errors (filament jams) look pretty much the same.
Could anyone help me debug this issue. My current solution is to either wait between prints until the motor is cooled down.
During printing it is no issue since the filament passes quickly enough not to heat up that much.
Or i am thinking of adding a fan for the gears.
Re: Overheated extruder motor melting filament
I forgot to add a picture:
Re: Overheated extruder motor melting filament
There are different theories about why some users have problems with this. For some reason, the extruder engine works so hard that it becomes overheated.
It may be due to low filament temperature, too high feed rate, the teflon tube in the extruder may have clipped or perhaps the Bondteck wheels are incorrectly adjusted.
I have not had such problems myself, even after 7 hours of printing.
Bear MK3 with Bondtech extruder
Re: Overheated extruder motor melting filament
You could try my fix for this issue here: https://www.thingiverse.com/thing:2867249
I had the exact same issue so I removed the spacing between the tube and bondtech gears to create a direct path.