Plug partway up filament (nozzle end) UM2+

[CatG 0]

I have an Ultimaker 2+ that has been causing me a few issues recently. At first I thought the tension on the feeder was too tight as the filament was just getting ground up at the back - however, every time I pulled the ground up filament out, the nozzle end of the filament had a plug about an inch up, disc shaped and usually split. 

 

I'm thinking that this is an issue with the coupler, but just wanted folk's thoughts before I disassemble the hotend or get a new one. What do you think? Image attached.

 

Otherwise the printer prints perfectly for the first half hour or so, usually does the brim and then stops feeding & grinds up the filament.

[geert_2 558]

I do not have an UM2+, only the UM2 non-plus, so this is just general guessing.

 

It looks like the heat travels up too high in the nozzle. So maybe you first need to check if the little fan works well? The one blowing on the filament and nozzle, which should prevent the heat from traveling upward? There could be strings of filament stuck in it.

 

Edited February 19, 2018 by geert_2

[gr5 2,224]

It looks like your bowden isn't in all the way in maybe.  Check that carefully and also make sure your third head fan works.

[CatG 0]

So I took the third head fan out, and lo and behold out fell a rogue machine screw that had presumably been stopping the fan from turning properly. Got a test print running now so my fingers are crossed that that was the issue. 

 

Thank you! Hopefully I won't have to get a new coupler after all.

 

[Edited just to say that my printer is now printing perfectly again :)]

Edited February 20, 2018 by CatG