Check your extruder again.
It must not slip at 12mm/s print speed...
Does it have a tensioner screw you can adjust? Maybe it is clamping the filament way to hard. If the tension is to low, it would grind into the filament.
Also check the Vref of the extruder driver, it might be to low..
It must not slip at 12mm/s print speed...
Does it have a tensioner screw you can adjust? Maybe it is clamping the filament way to hard. If the tension is to low, it would grind into the filament.
Also check the Vref of the extruder driver, it might be to low..