Filament eventually grinds because of back pressure, what else can I do?

[JaisonGreen 0]

I am not sure what else I can do about this. Here is what's going on.

To preface this - I have an Ultimaker 2 and 439 print time on it. It is fairly new.

I can start a normal print and eventually after maybe an hour I will start hearing the filament feeder start slipping as it's feeding filament in. If it is a long print (8+ hours) the filament will stop coming out of the hot end. After the print looks like it has failed, I abort the print and then pull the filament out of the hot end to inspect it. The end of the filament is mushroomed and definitely looks like TOO much filament is getting pushed into the head. Or maybe not enough filament is coming out. Although, the print's look totally fine (until it fails).

I have tried cleaning out the head using atomic pulls. I can see light through the hole of the hot end and I don't see any obstructions.

Any clue what I can do to try to slow down the filament? Does this even seem like it might be the culprit?

Thanks for any help!

[IRobertI 520]

The mushrooming of the filament makes me think that your PTFE coupler might need to be replaced.

Also make sure that the little fan at the back of the print head is running (either immediately when the printer is turned on or after the head reaches ~40C depending on which controller board version is in your printer)

[JaisonGreen 0]

Fan is working just fine.

 

The mushrooming of the filament makes me think that your PTFE coupler might need to be replaced.

 

Could you explain this one a little more? When I inspect it, the filament is fatter at the very end because its trying to shove more material in than is coming out. I could be perceiving this wrong.

Could you explain

Edited January 5, 2016 by Guest

[IRobertI 520]

Maybe it's best if you post a picture of the end of the filament.

But what I'm talking about is the white piece that sits in the middle of the head between the spring and the hotend. This is a consumable that degrades over time and needs to be replaced occasionally.