Filament breaks off overnight
So, I am a teacher of a high school robotics program and we have several different 3D printers. We primarily use a Robo 3D 1 plus right now. Every night after we are done printing, we turn the machine off and go home. When we return in the morning, the filament which worked all day without issue, has broken off at the point that the filament enters the extruder. This happens without fail every night. The filament we are using is from Vellemen. This does not happen with the Robo 3D filament.
Any suggestions as to why this is happening? Is it brittle?
PLA does this when it gets old. I'm not sure whether it is due to the hygroscopicity or breakdown from UV exposure, but in any case it causes the filament to become increasingly brittle over time. Temperature also has an effect. It likely becomes colder in your classroom at night, which makes the filament even more brittle.
I wonder if drying the filament in an oven at 160 F for a few hours would help this problem