Posting this in case it helps anybody else who has problems with failed prints due to the extruder hobbed bolt chewing through filament. I’ve been having problems with this for several months on my TAZ. There are a lot of posts on this forum and elsewhere about this issue, and lots of suggestions about how to fix these problems. However, as far as I can tell, very little has been said about the effect of retraction settings on extruder jams and filament chewing.
Anyway, I’ve gone through a lot of the suggestions over the past months with mixed results. At times I’ve had a lot of successful prints, and other times I have one failed print after another with the filament chewing problem repeatedly. Most recently, I was trying to print the fan shroud for building a new extruder assembly. Over the past couple days, that print failed close to 10 times with the filament chewing problem. I finally stumbled on trying to tweak retraction settings. By lowering the retraction distance and raising the minimum retraction travel distance, I got the shroud to print twice perfectly.
Upshot is, if you are having problems with filament chewing, and especially if your hot end does not seem to be clogged, then take a look at your retraction settings.
Hope this helps somebody…