Makerbot Replicator 2 cant print for some odd reason

[CADstudent]

The Filament we use is from Gizmo Dorks, Prototype Supply, Makerbot, Deltamaker, its all PLA and are filament is off to the side so no preheat action is happening and it seems to roll fine and it all seems to be action the same but still it makes no sense cause as you see in the picture how the end bloats up, the heat block should melt it down but instead kinda just melts a tiny bit leaving that thread like end

[Feliks87]

you won't believe what happened to me today

after printing for almost 10h yesterday I returned to my Rep2X today with a new job and it messed it all up
it must have somehow clogged over night because it wasn't able to feed the filament correctly

after several tries of load/unloading the filament I decided to clean the whole extruder head
guess what I found, this looks a lot like your filament (it's ABS btw from NuNus)
clearly visable "bite marks" from the stepper motor on the filament


I then disassembled the feeding mechanism and it was all crammed with filament debris from the unsuccessful feeding tries
but after cleaning up this mess it still couldn't feed the filament (because of the clogging I guess?)


the problem here is obvious right? bad filament
wrong... I loaded the very same filament into my left extruder head and printed right away without any problems (for several hours now)

so it seems to me that there is a problem with the feeding mechanism itself but what could it be?
I guess you have checked your feeding mechanism already CADstudent?