I recently modified my printer from a direct drive extruder to duel Bowden extruders. I did this so I can print in two colors. I like the set up and it works great with ABS. I recently began trying to print PetG and I had all kinds of problems pushing it with my new Bowden setup. I bought these extruders so I could fully contain any filament and possibly print with flex.
After examining the failures, I decided my extruders weren't build properly and the PTFE tubing could bend or flex right where the filament entered it. I designed and printed a filler that solidly holds the PTFE tubing at the gear. It clips on from the top.
So last night I started a print with PetG and this morning it was complete. Some problems on overhang, but the extruder made it through a 5 hour print without spilling filament. Maybe I have it right this time.

Edited 1 time(s). Last edit at 05/11/2017 11:35AM by cwaa.

Here are some pictures of the setup:



Top view of the extruder and you can seet PTFE tubing is up against the gear, but not supported for about 1/2 inch.



The top of the other extruder with the clip in place. You can barely see the filament at all.