PETG getting jammed during print

I’ve been printing with PETG lately and getting quite good at it. But every so often when i have a part that is taller it jams right around 45-50mm.

It will print everything up to that point really nice and fine then somewhere in that zone it grinds the filament and can no longer extrude it. I’ve pulled it out and cleaned the teeth and area but it continues to happen from time to time. I recently did an 18 hour print and it happened at 46mms and needless to say I need a solution to this problem as i like PETG filament for my needs.

Lulzbot Mini
Simplify 3D: 3.1
Settings: speed: 45 or 55 mm/s
.26 layer
cooling 90-100%
temp 242 C

MatterHackers PETG: its happened with grey and red.

I had a similar issue recently where two prints failed at the same point and I thought it was a jam. It turned out that my filament was simply bound at the spool. At some point I had let the end of the filament pass under another strand. Eventually during the print, it would get to a point where it locks up tight.

Check to make sure the small “blower” fan that cools the fins above the print head is spinning. Failure of those fans is pretty common; they can “ingest” small filament threads (particularly the ones PETG creates) and get jammed up. If that fan doesn’t spin freely, the feed tube can overheat, then the filament softens in the tube and jams above the melt chamber.

Does that area of the print have a lot of retractions? I find PETG can do that with a lot of retracts. Increasing the extruder temperature helps a lot with that. I also changed some slicer settings to retract less frequently. I often run the extruder at 275C for PETG prints with a lot of retracts.

Thanks for everyones input. Ive been looking at the possible issues and the filaments seems to be getting stuck and not being able to be pulled into the extruder. Im going to design something to help it roll better on my Mini.