Turnigy Fabricator - Printing narrow Party prolem

[PhilippG]

Hello.
i have aproblem with some printer-settings using ABS.

Every time some pieces of the print are getting narrower, they start to be printed "not solid". Since i have no better description of it, i have attached 3 photos.

Photo 1: http://ablage.gromotka.eu/3dpost/img3.JPG
The piece as seen in Cura.

Photo 2: http://ablage.gromotka.eu/3dpost/img1.jpg
The printed piece after i have stopped the print. Support-material still attached.

Photo 3: http://ablage.gromotka.eu/3dpost/img2.jpg
Supportmaterial is now removed. If you look at the columns, you see that it started to print very poorly. This always happens, when parts of my prints are getting narrower.

I don`t know, what to do about it. Has anybody any input on what setting might be changed to get a better result?

Thanks for any input.

Info about the printer:
It is basically a Ramps/Marlin Board, made into a package by Hobbyking. I am using Cura as a slicer.

@topic:
Curios that my two spelling-mistakes in the title did not get corrected, when i edited this post :-(

[joop1987]

Can you post your ABS settings? Are you using the original hot end? Why does your bed have globs on ABS on it?

[PhilippG]

Hi joop,
thanks for your reply.

I was using ABS-Slush on the plate to make the print stick better. Since i did not clean up the surrounding area after a previous print, i had bubbles of ABS on there.

I am using the original Hot end.

Settings:
Image 1

Image 2

I am using the german version of cura so, if anybody has a problem reading something, i will try to translate :-)

[curious aardvark]

you've got WAY too much abs in your slurry. For painting on buildplates it needs to be pretty thin. That looks like thick paste.
That aside it looks like you're printing too fast.

The layers aren't getting long enough to cool, so it's still soft when the next layer goes on and it won't go on clean. This is why it only happens when there's less to print. The layers are printing with less time inbetween.

Print speed is slow - but your printing and bed temps are very high.

Most abs will print at 225-240 quite happily. Build plate shouild be around 90 - NOT 125

You either need to print something else at the same time or use active ducted fan blowing on the print area.
And lower printing temperatures.

[PhilippG]

Thank you for your advice

The slurry worked fine on all previous prints. With thinner slurry, i got lifting edged from time to time. Since i made it a thicker mixture, i hat no failures like this.

In regards to the temps:
With lower Temps at the hotend, i had extraction-problems. I might try to lower them again some time later to see, if i can tweak it.
The 120° Bed-Temp was because i had adhesion-problems with lower temps. During printing, the bed is at about 115°.

I will try a print with "minimum time for a layer" increased.
This should help, i think.
Will post the results later.

[joop1987]

Turn your extruder temp down to 240 Deg C. At 250 Deg C you will melt the PTFE tube inside your extruder and damage it. If you damage it, it will keep on clogging when the molten ABS is pulled back during retracting. Besides that, try setting the filament diameter to 1.75, flow % to 95%. The original Esteps/mm is set to 95 and will extrude too much filament. Change it to 83.7 (Control-Motion-Esteps/mm-83.7).

[Sebastian Finke]

The slurry worked fine on all previous prints. With thinner slurry, i got lifting edged from time to time. Since i made it a thicker mixture, i hat no failures like this.

My mixture is also quite thick. Don't worry about it, as long the print sticks to the bed all is well.

In regards to the temps:
With lower Temps at the hotend, i had extraction-problems. I might try to lower them again some time later to see, if i can tweak it.
The 120° Bed-Temp was because i had adhesion-problems with lower temps. During printing, the bed is at about 115°.

Your temps are way too high for ABS. Extruder is ideally about 230 degrees (can vary from filament to filament). The bed should no hotter than 95 degrees.

I will try a print with "minimum time for a layer" increased.
This should help, i think.

Increasing layer time often just makes the print more slowly, not sure about Cura though. Another way to increase the layer time is to use purge walls. This has the advantage that the hot end moves away from the print completely at the end of each layer, allowing it to cool more effectively.

[joop1987]

I just remembered too, when using ABS don't use a fan. While the fan makes it easier and look nicer, the item will be weak and brittle. To increase drying time print multiple objects.

[curious aardvark]

I just remembered too, when using ABS don't use a fan. While the fan makes it easier and look nicer, the item will be weak and brittle. To increase drying time print multiple objects.

sorry but that's just nonsense. Abs prints are just as strong but much cleaner and sharper with fan.

One thing you can do is make a 5mm cylinder the same height as your print. uses way less plastic than a purge wall - but has same effect.
For longer cooling times use two at opposite corners of your build plate.

[PhilippG]

Thank you very much for all your Feedback!

I have been printing different models now and simply increasing the minimum layer-time seems to work. So the problem realy was my impatience :-)

Solutions: increase min-layer time, print purge walls, print a cylinder.. or (my favorite) just printing multiple objects (of nealry equal height).
I will try to experiment with those.

@temps / slurry
Since it was suggested, i thinned the slurry a bit and lowered the temperature.
I am down to about 100°C. I will go on lowering the temp with the next prints until i run into problems.

@ fan-topic:
I think this would depend on the fan. If your fan is too powerfull, it might cool the plastic, before it has a chance to bond with the layer below. So under certain circumstances / with certain printers, this might really be a thing, i guess.
So both of you seem to be right.

All in all, my problems seem to be resolved by now. :-)
Thanks