So I'm getting weird, temperamental under extrusion, and I have no idea why. I cleaned the nozzle not too long ago, and I'm doing another print with a 110% flow rate and its still the same. When I did the prints in the picture, I printed the clean one first, and then right after did the bad one, and it makes no sense. Its not Cura since the settings like I said are the same and the increased flow rate does nothing.
I was getting a bunch of this after some pretty intense printing this week. I've had mine for just over a year now & should really count myself lucky for not having any extruder issues until now. After fiddling about & browsing the ol' YouTube for a couple hours I narrowed it down to 3 possibilities, Something wrong with my Z axis, something wrong with my X axis, or a jammed nozzle. Turned out to be a jammed nozzle in my case. After snapping a drill bit inside the nozzle I gave up on cleaning it. Luckily I had some spares I ordered for this inevitable dark day. So after installing a new nozzle it was still jammed up. Looks like I got a jame in the throat somehow. More YouTube browsing....
Eventually I figured out I just needed to do a cold pull to fix it. Old spool of ABS to the rescue. PRe-heated for ABS with the little bit of PLA still in there. I nipped it right at the top of the throat under the extruder gear, forced what I could down in there with a dental pick, then I just rammed some ABS down its throat until I got all of the PLA out & started seeing pure ABS. Set the printer to cooldown & began pulling the ABS back out the top once it got below 180C. Then I just repeated these steps until I was certain I was getting 100% pure ABS. Pre-heated for ABS again, & fed new PLS down the throat until only the PLA was left. NOw it's printing beautifully again.
I hope in your case it's just a matter of lubing up your X rails & calling it a day.
Here's Joel's video on doing cold pulls. He's doing it on an Ultimaker with some nylon, but the same principal applies. I just used ABS because that's what I've got for higher temp than PLA. I do know you can pull it off with a new bit of PLA, it's just dicier. Good luck & hopefully that helps.https://www.youtube.com/watch?v=MGt8cnVIKW8
So for me it was a clog and a worn out nozzle, i fixed it but it came back, and it was a clog again, and i havent done the cold pull yet but i do believe i fixed it by just heating it up a ton then pushing filament through. If i get this problem again i will try the cold pull
Power supply is fine and same with the inside of the nozzle, I found out that the problem WAS the nozzle. I've been using the same nozzle for a year now, I never thought it would wear out, it did, its now about 0.8 mm. Im getting a new nozzle.