Nozzle stuck in Ollson Block because of burnt plastic

[JFR 0]

Hello everyone, I am currently suffering from kind of a problem with my Ultimaker 2+, which worked flawlessly up to this day. I really wanted to contribute to the community soon, so having to ask for help as my first post is not really how I hoped to start here.

When I wanted to switch my nozzle today, the nozzle wouldn't even move at all. After like 20 minutes I finally got it out, with way more force than I like to put on delicate parts like my print head. It was so hard to turn it, that even my 3d printed torque wrench gave up and broke on me. I hope my print head is ok.

Now, I have already figured out the problem. It seems that some plastic, probably a string from when I changed materials and nozzles earlier on, got in between the thread of the nozzle and the inner thread of the Olsson Block. I even found some burnt debris inside the housing.

Now, removing it from the nozzle was easy with a lighter and a fine needle to make it a bit softer and then scrape it out of there... but I have no idea what I can do with the inner thread of the Olsson Block. How can I free up that? Does anyone already have to deal with that kind of situation and what did you do?

Thanks in advance for your help and responses!

[owen 19]

You should be able to heat the block up with the printer without the nozzle in their and then use your needle again to clean the block.

[JFR 0]

Thanks for your reply. I kinda tried that, but can't really reach every spot. Especially behind the point where the thread ends and there is a little gap to the next metal part, it seems there is a lot of stuff stuck.  

I was a little bit successful by heating it up repetitively and screwing my steel nozzle in and out, again and again... plastic got stuck in the thread and I could get a bit out that way.

At least I can now change nozzles when I heat the block up enough, because the burnt part of the plastic that was stuck seems gone... as soon as its cooled down, it is hard as rock though. Now I am afraid that more of that stuff will burn when I do a longer print and get the nozzles stuck again.

Edited February 12, 2017 by Guest

[ahoeben 1,766]

Especially behind the point where the thread ends and there is a little gap to the next metal part.

 

It is very important there is no such gap. It could become the cause of many nozzle clogs. The path of the meltzone should be as continuous as possible.

[JFR 0]

 

Especially behind the point where the thread ends and there is a little gap to the next metal part.

 

It is very important there is no such gap. It could become the cause of many nozzle clogs. The path of the meltzone should be as continuous as possible.

 

Actually, I guess my wording was kinda bad there. With gap, I didn't mean a gap in the extrusion flow, just a small cavity behind the thread of the block.

Of course all the plastic in there caused a little bit of a gap as well, which does explain where the burnt blobs, that were in my last few prints, came from.

However, I guess I'm fine now. It was a tedious process to clean it out, but in the end I think I have gotten most of the stuff out. So thanks for your replies and messages!