Bambu Lab Black ABS ringing / ghosting

[FredrikB92]

Hello, so i am having some issues while printing Bambulab Black ABS on my H2D. The prints finish without warping but the walls are not pretty and full of what i think is ringing or ghosting.

Before we get into my print settings, drying etc. I want to add that i had no issues when printing PLA, PETG and Nylon-CF from different vendors including Bambu Lab before trying the ABS spool.

This is my first spool of ABS ever, and i dred it in the AMS HT at 80 degrees for 8 hours, because my first ever print clearly indicated that the fillament was wet.

But all the following prints after the drying has this ringing issue as shown in the pictures including my print settings

Settings & Preparation summary:

1. Dried in AMS HT 80 Degrees celsius for 8h

2. Bambulab ABS default fillament profile with 65 degree chamber temperature.
   2.1 Tried both with and without
   “Slow down for better layer cooling”
   2.2 Tried lowering the print temp by 5 degrees,
   With no visual impact on the finished print

3. The full print settings are show in the pictures. But the general settings for the prints i’ve tried are
   3.1 Precise walls enabled
   3.2 Avoid crossing walls
   3.3 Inner/outer/inner wall order
   3.4 Four walls
   3.5 25% Adaptive cubic infill

I hope someone can help to point me in the right direction for my troubleshooting.

[MalcTheOracle]

Have you tried the calibration tests on the filament?

Flow Dynamics Calibration

[FredrikB92]

No i have not done that because i use the automatic calibration which the H2D provides during the startup sequence of a new print.

But might be worth try.

I also have a P1S, so quite used to manually calibrating the K-factor

[MalcTheOracle]

What does it look like on your P series?

[MK4S_H2D]

Since it’s on the whole surface and not just close to the edges I’m not too sure that extra flow dynamics calibration will help/change a lot.

Things that might help:

• printing walls faster
• enabling “don’t slow down outer walls” (I believe from the top of my head this also overrides the two smoothing features on outer walls but I’m really not sure, otherwise also try playing with the two smoothing options on the quality tab)

[FredrikB92]

I have not tried on the P1S yet, its been busy with some christmas gifts. But i will give it a try when it is avaliable!

I did however find something funny with my Nozzle and temperatures. Running a few test prints with different settings after i changed nozzle.

Will post the result when i have enough data!

[FredrikB92]

I have now gone through a rabbit hole and managed to make the surface finish way better. I am not sure however if i have fixed the actual issue. But i will go through my findings here. And hopefully any other people with the same issue can try my steps

I also re tightened the X and Y axis belts with no changes to the ABS print quality. And i also tested PLA and PETG which printed perfectly.

These pictures show the before and after. (Its hard to take pictures showing the results, but belive me the changes are huge)

STEP ONE: SMALL BUT VISIBLE IMPACT
My first step was to change the 0.4mm nozzle with the spare one. Fyi - the printer has only ran for about 140hours at this point printing mostly PETG from Azurefilm.

When trying to change the left nozzle it was stuck. Searching the forums i found more people with the same issue. Check the link for more infor

Unable to remove 0.4mm H2D nozzle hotend

Heavy heavy smoke that I’m assuming (and could very well be wrong) would also include some vapor sized particles of filament. Either that or maybe the filament oozes up with high enough temperature alone, kind of like solder and flux going to heat.

And behold i had the same issue. Some goo that was stuck between the nozzle and the heater.

Switching nozzle had a small but visual impact. What i saw was that the new nozzle heated to the target temp way quicker. So my theory is that the goo disturbed the temperature sensor making the nozzle print hotter than it was supposed to.

STEP TWO: MEDIUM VISIBLE IMPACT:
In step two i recalibrated the filament flow rate, max flowrate and temperature

These are the settings i changed on the Bambu Lab ABS filament.

1. 0.975 Flow rate
2. Max flowrate 20mm2 (Unchangedc could go higher, but did not want more variables then testing)
3. First layer temp 265, then 260 for the rest of the print
4. Slow printing down for better layer cooling “ON”
5. Dont slow down outer walls “ON”

The new filament profile had a visual impact, but it was still far from good enough.

STEP THREE: MAJOR VISUAL IMPACT

When doing the max flow calibration i noticed that from 5mm2 to 25mm2 i saw none of the visual artifacts i was used to.

But this calibration has almost no changes in acceleration and sharp corners. So from this i deducted that the acceleration settings must be whats causing the majority of the artefacts.

And behold it was. After keeping the original print settings as shown at the start of this forum post with the new nozzle and calibrated filament. Reducing the acceleration alot “fixed” the rest of the problem.

Outer Wall down from 5000 to 2500mm acceleration
Inner wall down from 8000 to 6000mm acceleration

My theory is that the viscosity of the Bambulab ABS filament cannot handle the jerk and acceleration as good as the PLA and PETG i have tested.

CONCLUSION:
I don’t want to use more time troubleshooting. The result is not perfect but good enough for me.

But reducing the acceleration not speed is what had the biggest impact on the quality.

Important notice! I have only one spool of Black ABS, it might be that i have gotten a bad one.

Hopefully this helps someone else with their problem or further troubleshooting.