I am having a consistent issues with my feeder grinding filament rather than feeding.  What does this grinding/feeding issue look like? When the filament gets stuck at the extruder head or flattened by the feeder axis, the toothed wheel grinds a semi-circle into the filament.  See here.  This is occurring nigh-constantly on Feeder 1 of my machine.  It always occurs during the same point of the cycle: about two layers in, the surface of the print begins to look sputtered as it is failing.  Then nothing comes out.   The device in question is an Ultimaker 3 Extended with up-to-date firmware.  I am running PLA to an AA core.  The issues have occurred across multiple brands of filament.  I doubt there are any humidity issues; brand new filament has problems too.  To date I have attempted the following to fix the issue:   Hot/cold pull of AA print core (the core pulls cleanly, so I doubt it is clogged). Feeder spring tension adjustment. Info at the bottom of this page. (When the gauge is at the top of the meter on the side of the feeder, it exhibits the issues described above at ~layer 2.  When it is below that point, it doesn't feed anything from the beginning.) Use of compressed air duster to clean ground PLA material from feeder. Info at the middle of this page.   What's going on here?  Is there something I have not tried to remedy this? Does anyone have a tensiometer which can be used to check the force applied by the spring of a working feeder?  Should I contact the distributor at this point to request help?   Thanks for your assistance.  I'd be happy to provide additional info upon request.