Black molten plastic in print

Hello Robo3D forums!

I recently got my hands on a new robo3D printer, and after, a lot, of calibration and learning how each type of PLA filament worked and under which temperatures they operate, I managed to get some decent prints out of the printer. So far, an AMAZING machine which really replaces the water cooler as the local hangout spot in the office.

Although, after some errors, a little bit of filament got stuck at the heat end of the printhead. During printing, black drops of liquid... goo smelling of burned plastic fell out of the printhead. Upon close inspection, some fillament dripped out underneath of the tape surround the printhead. I think that filament is not only coming out of the buttom but also a bit out of the sides.

Upon close inspection, a little bit of smoke comes out of it. This cannot be good. Is there any way to clean the printer, or am I doing something completely wrong?

The print temperatures, that give the best prints with my current PLA, is 210/205. Any lower and the filament doesnt stick to the previous layer.

I hope any of you guys can help me with this problem!

Bart

edit:
I removed the printhead and found out that there is a lot of filament coming out on top of the hot end. I read some problems with the hot end not screwed on properly and broken tubes of the printhead. Is there any way to clean this up, or do I have to get a replacement for this printhead? The first couple of prints went fine, 2 days later, it ended up like this.

 

Ouch, That sucks. did you ever figure this out? I wish I had an answer but am brand new to this as well.
If you run it up close to temp say 175-185 with no filament feeding I wonder if you can scrape away the excess and with the right tools since its hotter than hell possibly tighten it down after? But again I don't know.
Worst case it's an opportunity to upgrade your hot end for when you move on from PLA. Would have to have a heated bed by then as well.

 

A-ha! That would explain why my hot-end is also covered in molten plastic all the way to the top, even though it couldn't have collected that much during normal print... Luckily, I got myself a new E3Dv5, which I will be installing very soon.

 

Denys, once you install the E3D you want to modify your firmware so that it raises the maximum temperature. See sections C.2. and C.7. in the Robo 3D User's FAQ. In addition don't forget to print a new replacement PLA cooling fan bracket as the stock bracket does not fit with the new E3D installed.

 

I was printing the new fan holder for a E3Dv5, but it wouldnt complete due to too less filament coming out of the printhead, it was all dripping out of the top.

I got advised by the robo3d support to raise the temp to 220 and then try to pull out the tubing from the printhead, and tighten the hotend. I'm only a bit hesitant about it, because I don't want to touch the thing when its 220 degrees celcius... Will try to fix it this week, and will keep you posted.

 

And here are pictures of my printhead with filament seeping from above the hot end...

View attachment 2047

 

Denys, that, unfortunately, looks like a melted PTFE tube

 

Same thing happened to me. Cracked PTFE tube. It's a common issue and they'll send replacement ptfe tubes but yeah...

 

thats exactly what I had, I'm heating it up today so I can get the PTFE tube out. I will make pictures, according the Robo3D support it could also be that the hotend isnt screwed on tight enough. I'm just a bit iffy about touching the thing when heated up :/

I heated it up, grabbed it with gloves and pulled out the PTFE tube. It was clearly cracked, I included a picture for reference material for everyon who has the same problems!

 

Melody, PTFE tube can crack, but it can't melt under the normal temperatures we use, which is under 235C.

Bart, thanks for the picture! I disconnected mine before extracting the tube (too eager to install E3D

 

It was a cracked tube, confirmed by Robo3D support. They are sending new ones and I also ordered the E3Dv5, that will be a new challenge to install, but with the new PTFE tubes I can at least print the new fan bracket which is needed for the E3Dv5.

All in all, I'm quite disappointed by the fact its a cracked tube, and a common error. That should be fixed if it is that common. Although it is a new product in a new line of technology, and I loved the experience and am very gratefull for the fact that I gained a lot of knowledge about the printer by trying to fix it myself.

@Denys: When the printhead isnt heated up, it was impossible to remove the PTFE tube due to all the filament that leaked out of it. It fused itself with the rest of the printhead. After heating it to 180 degrees, I came out immediatly. So, it might be difficult to extract the tube when the printhead is disconnected.