I’m just about had it with this issue. Right now half the time I can’t even use my printer. Does a model require retraction? Forget about it, my printer jams up, the filament ground to dust. I’ve lowered the tension on my feeder, been told by support to try raising it instead, cleaned my the feeder, cleaned the head, done a firmware update, started using the most recent version of Cura, the only thing that made a lick of difference was replacing the entire feeder assembly with a brand new one. That lasted a month, now I’m right back where I started. I’m not even able to load filament right now because I get the same problem. I get a little squirt of filament out when I change material, I set the printer up to print, than nothing just ground down filament.
Is cura set to work with 3mm or 2,85mm or 1,75mm? Try to extrude cleaning filament by hand through the heated hotend to unclogg it, I’m pretty sure that a partial clogged is the reason for your issues. What material and temperature were you using and from which brand is the filament?
I had this problem with my UM2 (although not as bad as you). My solution was slightly loosening the 4 bolts half a turn, that hold the feeder on the back. No idea why this helped but it was what someone suggested to me.
I had this problem and found a solution. The reason why it was grinding on mine was because the filament reel was too tightly wound. Meaning it pulls back from the feeder causing it to grind as it is pulled back and forth. Simple solution is to loosen up the reel itself.
