I can print the calibration box and it looks good. But if I print for more than 30 to 45 min the extruder will stop forwarding the filament. I have had to fix some problems with the Hexagon hot end and have replace the thermistor. So I have done some work in the area of the extruder, but have not change anything on the extruder. I have a Robo R1 with the enclose bottom. I use standard Colorfab PLA filament from Printed Solid. I print in PLA, my hot end temp is 210c and my bed is 55c. I am trying to print the Thinking man from thingsiverse. should be about a 5hr print. After about 30 min the filament stop feed through the extruder hobble bolt. When I pull out the filament I can see where the hobble blot is biting into the filament. I think the problem maybe with the tension on screws that hold the filament against the hobble bold, I see the screws for increasing or decreasing the tension, but how do you know how lite or tight you should set them? The pictures are of my printer and filament setup. I don't think the filament is binding, I check it often and it seems to be rolling of the filament reel freely. Any help or suggestions are appreciated.