Extruder stops extruding filament

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.

 

mark is there anything I need to check out with how much preasure is being put on the filament as it rolls across the hobble bolt. This had been working, it stopped after I removed the hot end to replace the thermistor, I can print for a short period of time, 15 - 30min then the filament stops being fed through the extruder. Is there a thread that talks about how to season the hot end.

 

Thanks for your help, I will season the hotend and let you know how it goes, is there a permanent seasoner that I can print from thingiverse. One that you like or use?
Do you know what type of hobble bolt Robo is using on it's new printers with the Hexagon hot end, is this something I should look at replacing. I was reading on the forums about the old ones being a problem?

 

Mark is there a way I can determine if the tension that holes the filament against the hobble bolt is to loose or to tight.

 

Robert,
Did you ever put in a new hobbed bolt? Can you post a photo of your current one?

 

Steve, I'm using the original hobble bolt that came with this ROBO 3D printer. This is a newer printer, it came with the hexagon hot end and the enclosed bottom. I'm not sure what hobble bolt is being used on this printer.

 

Robert, I had the same problems and I done exactly what Mark said about seasoning the hot end, and after I cleaned everything I have been printing for hours and no more jamming.

 

Can you post a photo of the hobbed portion. From what I have seen they are still shipping the same bolt design with sharp angled hobbs on it. I suggest that you replace it because it tends to slice through the filament if there is a bit of back pressure from the hot end. Radial hobbs like on the ebay bolts work much better.

 

I think you might get some disagreement on that.

 

Sure someone can disagree, do you? My opinion is that slicing into the filament at an angle is is a good way to take chunks out of it and poor way to grip it. I agree that all I have is anecdotal evidence from this forum and my observations. My original bolt would easily accumulate plastic shavings, my radially hobbed bolt does not do this at all after a year of use.

 

It would be better to mount your spool above the printer and have it rolling on bearings. The more the extruder has to pull the filament from the spool the more likely it will chew it. The less resistance you have for the extruder to pull the filament the better.

 

Galaxius,
Originally I threw out the Robo3D's side mount and designed a top mount ball bearing based one. The ball bearings made it spin much too easily. I also did not like that the spool could fall into and smash my bed. I then designed a robust side mount one which just spun on a PVC pipe over a brass threaded rod. I have had not any issue with the resistance. Perhaps it is because my radial hobbed bolt has no problems pulling it .

(Edit- Forgot to add the link to the side mount: http://www.thingiverse.com/thing:516790)

 

SteveC, where did you get you radial hobbed bolt?