Brown Gunk coming out of nozzle

[PatrickM 0]

I bought my Ultimaker 2 about a month ago, and it's slowly turning into the worst purchase I've ever made. Ultimaker support is zero help. Recently, after printing for about 2 minutes each time I try to print, the PLA material stops extruding for about 10 seconds, and when it starts to extrude again, a brown, liquidy, burnt looking material explodes from the nozzle and wrecks the print every time. I'm using default PLA settings with the nozzle temperature at 230. I even bought a new nozzle and that didn't fix the problem. Can someone please help me? Ultimaker support definitely won't help me.

http://imgur.com/gallery/zvvjpol/new

This is a picture of the issue

[gr5 2,170]

It could be a bunch of things. It could be water droplets on the filament in which case you would hear a little pop and it would spit out extra filament followed by zero filament. It could be the head is hotter than you think - definitely test for that (video below) and it could be normal retraction due to too much pressure where the feeder skips back a bit followed by no extrusion for a few seconds although usually you don't get "burnt" after that.

To diagnose better it would help to have a video and also to show your settings for: print speed, infill speed, nozzle temp (I know, 230C) and layer height.

Here's how to roughly test that temperature is correct. Also please post what country you are in as part of your profile settings (the location field) and which support option you went with (did you do support.ultimaker.com?).

 

[gr5 2,170]

Also inspect the first meter of your filament both inside the tube (look through it from two directions) and coiled. Is there dust, durt, water, gunk, anything on the filament?

[SandervG 1,521]

Hi @PatrickM,

Thank you for your email.

Where are you based? Regardless of your issue Ultimaker support should be available for you.

I would be happy to point you in the right direction or pull some strings.

Obviously, the forum is also a great place to find help!

Did you already install the new Nozzle? It looks like there is some residu in your nozzle, or possibly the teflon is showing some wear. Depending on what speed you are printing at, 230ºC is probably fairly hot and you may be burning your PLA.

Looking forward hearing from you!

[JohnFox 25]

230C is too hot for PLA, the machine default is 210C, I would stick to that for the time being as it looks like the PLA is being degraded. Once it starts to degrade, gunge will build up in the nozzle and may hinder the flow.

What make of filament are you using?

[nallath 1,120]

230 isnt a default in any software / firmware that we make. Cura uses 220, but we changed that to 210 for the new Cura.

The brown gunk is indeed degraded fillament.

[neotko 1,417]

If you need 230 because you plan to print really fast you need to adjust the first layer heat so it doesn't burn the pla. Since first layer goes slower (to stick) the pla it's staying too much time on the nozzle. You can use Tweak at Z to make the layer 2 go slower and raise the heat gradually. https://github.com/Dim3nsioneer/Cura-Plugins/wiki/Tweak-At-Z-plugin

I use s3d that allows to place different C for each layer and to print 100mm/s at 0.2 I start at 210-215 and then on layer 2 I raise it 5C and so. This way you can have a good slow first layer and avoid pla burnings/brown.