I have had this happen myself on my Rep-Rap A LOT more then I would like to say, but I did find out a few things as I was pulling out my hair and as I was learning how to use my printer and keep it from doing this.
1) Not all ABS and PLA print at the same temps. I have found that some print at 220C while others print better at 230 and 215 for the ABS and some of the PLAs print at 175 perfect while others where better in the 180 range.
2) My print bed was not as level as it should have been causing the printer to back up in spots and not extrude as much plastic in that spot as in others. This caused a sort of clog as it printed because it was pushing to much "water" threw the opening for the space to allow.
3) My feed was faster then my print rate ( I was tinkering some with how things printed and forgot to set this part up at times )
4) To much tension on the filament seemed some times to be a bad thing BUT never caused the hob chew to an extreme unless it was way to tight.
5) (THIS IS A BIG ONE THAT IS OVER LOOKED A LOT) Your spool is not on a spindle of some sort to help it so it dose not have drag on it as it prints, this causes the filament to not be able to be pulled in with the hob bolt as it is fed into the printer.
6) ( This one kind of goes with 5 ) your filament is twisting as it is pulled into the printer and this causes tension on the filament in the spool causing it to not freely be pulled into the printer.
How To Fix And Prevent
1) Test print new filaments on a small print and see the ideal melting temp before you do large prints.
2) If you do not have one already get your self a drop dial/ dial gauge and print off a dial gauge holder for your X axis to level your print bed with. ( can be found on Thingiverse if one is in need and can print one)
3) Find a feed rate that works for that print speed ( takes time but some times is worth it )
4) Loosen/ Tighten the tension some and see if that helps
5 and 6) Make a spool holder that holds your spool so that is can pull in the filament freely with little effort. ( some times you can find them on Ebay for under $30 USD with shipping included, that are really cool that work wonders on most spool sizes and printer types.)
Hope this helps you or even some one else that is going threw this situation, I hated when my hob decided it was hungry and chewed up my filament in the middle of a print, caused me to lose a lot of filament that was unusable after.
( I will try to post so pictures soon with this of good and bad )
We are left now with only one option...and that is without a single drop of rum....