Brown Areas

[jan]

Most of my prints are showing some brown areas (photo). At this areas, the print also becomes quite uneven and messy. So far, I couldn’t figure out why they appear. I usually print with standard settings.
Today I did two prints (one after another) of the same object, and it seems that the brown areas appear exactly in the same are in both prints. It seems to be a repetitive issue, but I have no idea why it happened in this areas. Maybe know the reason?
Thanks for any suggestion!

brown areas.jpg (173.55 KiB) Viewed 401 times

[pp3dp.nl]

The brown area is at the top because that is where the nozzle is for a longer period of time and the ABS curls a bit because of the relatively high temperature. Then it is possible that the ABS touches the nozzle where the brown residue forms and it is then transferred a bit to the model. Which ''wind barrier'' do you use? Maybe with the more cooling version (I believe version 6 or so) the model doesn't get as hot at the top. Or print more of the same model if you can so the nozzle has to move away from the top for some time and that area can cool a bit.

Hope this helps...

[eyUP]

Because the top part is a smaller area, those layers are staying softer and sagging.
Either try cooling it quicker with a different wind barrier / deflector or print in fine mode which is a bit slower.
I'd also try rotate the model (half way between the top and bottom pipe angle, say 15 or 20 degrees ?) so that the majority of the build is straight up and down.

[wilsonj]

I had exactly the same issue when I first started printing. The windbarrier 7 fixed it.

[jan]

Yeah! This solved the problem. Turned out that the fan was mounted wrong, so there was no cooling at all! The cable to the fan was too short to get it in the right position. Fixed everything now.
Thanks so much for you help!