goldblam

Even printing as slow as possible the filament will stop extruding or won't be able to start extruding. Have tested temps from 180 up to 250ºC and still it can extrude manually, but will not print. Sorry forgot to say it is a Ultimaker 2, and I have 3 other Ultimaker 2's that are completely functional, its just this one giving problems. And this printer usually works wonderfully, but in the last couple of weeks it has had this problem.

When I manually move / feed material through the hot end It moves through flawlessly. Its been cleaned many times to make sure that stuff stuck inside clogging it is not the problem. Have stuck wire through and can see all the way through the hot end, and it moves material, but it can't print. When it prints it starts and does the first layer alright, but quickly the extruder starts skipping and filament is not extruded. I believe the ceramic in the hot end has some sort of bump on it which stops retracted filament from going through again. Do I have to replace the hot end? Is it possible to ream the ceramic to get rid of the bump? any help would be great, --Mike