ABS filament feed problem

I have had my Lulzbot Mini for a couple of weeks now and have been printing almost every day with ABS filament. Today it stopped in the middle of a 2 hour print. A test extrusion failed to extrude filament. Removing the filament revealed that the filament had a gouge in it made by the hobbed bolt. I cleaned the hobbed bolt and the print nozzle and tried again several times to get the filament to feed, getting the same results – the hobbed bolt would gouge the filament and stop feeding.

I noted that a few other posts noted problems like this with two possibilities: heat creep and idler screw adjustment. I ruled out heat creep because that is supposedly a problem with PLA only and the worn part of the filament wasn’t warm whenever I removed it. Another post stated that the separation between the washers on the idler screws should be about 5 mm. Though the distance appeared to be about 5 mm, I tightened them to be a little less than 5 mm and this seems to have cured the problem for now.

I thought I would share this information in case anyone out there sees the same problem and, heaven forbid, if my feed problems should return.

Sometimes over tightening the thumbscrews can cause the toolhead to strip out the filament like you are describing. If the problem returns, try loosening them up just a little bit.

The other thing that I’ve noticed is that sometimes the way a particular print is done, there is so much fast extrusion, retraction, extrusion, retraction quickly that it will cause that wear. I’ve found that by either slowing things down a little bit or by changing the retraction distance, I can normally make that go away. This is the type of thing you’ll sort of figure out over time.