UM2E Feeder Stripping Filament Regardless of Tension Setting

[skjbTHI 0]

Hello Ulitmaker community,

 

After taking apart the feeder for cleaning, putting it back together, and re-attaching it to the UM2E (a process I typically do once a month or so), I noticed that filament is being ground/stripped in the feeder, preventing any material from being extruded once the print starts - the printer will motion over the print area without printing anything. This seems to happen regardless of how tight the tension in the feeder is set. I've had it at max tension, min, and most stops in between, all with the same result. 

Manually moving filament using the 'move material' command is no problem, as long as I'm not attempting to feed an already-stripped portion of the filament. Similarly, loading filament is no issue; the feeder will grab the material and advance it no problem, up to and including extrusion of said material from the nozzle. 

 

Prior to a print starting, as the machine is heating up, material will extrude from the nozzle before the print begins, as normal, up to the point where the print begins. At this point, the material promptly ceases extruding and won't start again. For reference, I print with PLA and Ultimaker tough PLA.

 

I've cleaned the nozzle using the atomic method (cold pull looked great), and the bowden tube is clean, leading me to believe this must be a feeder issue, but since no modification to the tension screw seems to make a difference, I'm scratching my head as to the cause of this problem. Any help would be appreciated.

[skjbTHI 0]

Quick update in case anyone else is searching for this issue. Turns out the feeder was functioning fine, but the bed leveling was off—the nozzle was far too close to the build plate and material couldn't be extruded, causing a backup in the feeder which resulted in the grinding. Problem was solved by re-leveling the bed. How the bed got pushed so close to the nozzle without me adjusting the level is a different problem but one for another day!