Originally shared by Kurt Meister
Graber i3: Material flow - solved
The hassle seems to be over: I finally figured out that the hobbed pulley was responsible for the main material flow issues. That’s on one side perfect. 
On the other hand ist kinda embarrassing: I expected the problem at the E3D hotend and tried to solve it by seasoning the heat break.
When I some days ago printed a calibration cube (ehm, I mean a column), I noticed a pattern within the issues. When I then analysed the hobbed pulley, I spotted the problem: The grooves were not totally machined.
Thanks anyway to @Brad_Hopper @Thomas_Sanladerer @Jonathan_se5a_Sorens @Eclsnowman @Tim_Rastall @Adam_Thorp @Paul_Chase @Liam_Jackson @Tom_Oyvind_Hogstad @Mike_Miller
