Constant under extrusion and filament grinding I sadly have a big problem since a couple of weeks and I cant fix it myself. For over 20 prints, I had the same problems: At the start, everything goes well but at some point of time, my Creality CR-10 starts under extruding and after like 1 minute, NO filament is extruded anymore and the 3D printer moves over the printing bed without extruding anything. After that, I have to pull out the filament and the feeder always grinds into it.

Some problem with the hotend (so the feeder works well but it cant push the filament through somehow - I cleaned the nozzle and couldn't find anything wrong there. When I push the filament through by hand it gets extruded but after a failed print, it is VERY hard to pull it back (because of the filament being slightly bigger at the nozzle - hard to remove! - 

That could be the problem:

I just tried to remove the filament from the printer (another failed print) I had to use two tongs because the filament was so hard to pull back. I noticed that the diameter of the PLA close to the hotend was a lot bigger (way over 1.75&nbsp;mm) For about 5&nbsp;cm that's a very long distance - that's the reason why it's hard to pull back (and also push through?) But I don't know why that happens... If I get an answer for that, I think that I have solved my problem

I already tried printing at 50&nbsp;% which didn't work.


Creality CR-10 with 0.4&nbsp;mm nozzle, 
1.75&nbsp;mm PLA filament used (white)
0.27&nbsp;mm layer height
45&nbsp;mm/s printing speed at 220° (I can easily push the filament through at 200° by hand)
60° bed temp


And here some pictures of the failed prints:









I think I can exclude these:

It could be: (the things I can imagine but don't have a solution for)


The feeder being too strong/my new PLA filament being too soft
Maybe a software problem? I'm using the newest Cura version and I don't know what could be wrong there.


The filament seems to run out of the hotend. Something is really broken here. I tried to lower the print temperature and don't have an issue (at least not that big) with pulling out the filament but instead, the feeder started grinding into the filament again.



I'm very happy for any answer and possible solutions.
Grinding is due to attempts to advance filament faster than it can be melted and dispensed. Try one or more of the following:


Raise the head temperature (to meet current throughput demand)
Lower the print speed (to reduce throughput demand)
Slice for thinner layers (to reduce throughput demand)