stops feeding PLA in the middle of a print?

Printer has been working good for awhile and haven't had any real issues. Tried to use it today for a 6 hour print and it printed about 10% good then after that the printer continued to do its thing but it stopped feeding filament.
So no big deal, unloaded it, loaded it and it was fine. Tried it again and same results, this time I noticed a kink in the back where the filament was feeding into the liner. No big deal, started it again and again 10% or so through it it stopped feeding the PLA.

Could it be a bad spool of wire? Tried it on 2 different files and same results. Any ideas on what is causing this or how I should fix it?
I want to try using the other extruder but not sure if I had to change the settings before exporting it or if I can just shove PLA into the other head and hit go.

Make sure the filament is wound properly on its spool - specifically that it is not wound with overlaps that can stop the extruder gear from feeding filament. I had this problem with one spool and had to completely re-wind it onto another one.

Also make sure the "teeth" in your extruder gear are not clogged. There should be zero slippage when the gear feeds filament. Sometimes the gear teethgets partially filled up with filament dust and this can cause miss-feeds - or no feeds.

Ah good to know. I'll look into it. Thanks

So I think I got past that point. I keep trying to continue my print and keep getting this. I tried 2 different rolls of PLA. Never had this issue either. I also re leveled the bed and all is good there.
This happens maybe between 30- 50% through
http://i46.photobucket.com/albums/f1...pssifsk11p.jpg
http://i46.photobucket.com/albums/f1...psuiejqpx9.jpg

lol been printing non stop since last night and everyone has the same issue.

well it's a crap finish - but what's your actual problem ?

that is whats happening halfway though the print so i just stop it early and toss it. otherwise the nozzle keeps hitting it every time it passes over it.
Not sure what else to check. bed is level, tried 2 rolls of pla, tried higher temps from 208 to 211 on the pla and bed at 50 and 55*C. not sure what else, but i'm ready to pull my hair out

You calibrate your extruder correctly? Is the filament diameter correct? Just throwing some obvious ones out there...

Since it is PLA, have you put a fan to cool everything ?

one thing that might make a difference is the difference between print speed and travel speed.

If you print at say 50mm/s and have your travel speed at 100mm/s I find that the sudden acceleration often pulls soft filament up and creates those sort of peaks that heads will catch on.

These days I pretty much make the travel and print speed the same. This avoids the pulling on soft filament.

Hmm that's a good idea
Filament was set to 1.77 and it's 1.75 diameter so I changed that.
Print speed is 50 and travel speed is 150mm. These are all default setting I never changed anything. So i'll try what you said and i'll knock the speed down to 100 and see if that makes a difference.

Just my luck, both print heads are jammed. I tried to stick a sewing needle in there with no luck. Any other ideas? I took the fan off and can't visually see anything.

Printing much better now. but still have a rough finish on the top. Wonder if there is a setting for the finishing layer and what I should change it to?