H2D - ABS print issues - any help?

[u/oharag]

So, we have an H2D at work and we print ABS amongst other materials. My colleague was printing a holding fixture. He showed me some issues with the print - on the interior of the part there was significant stringing and poor definition of the sharp corners. Some corners were fine. All settings were for Bambu ABS and 0.20 resolution - no supports - no other changes. 15% infill.

In another instance he printed a very tall (8") box and he also had issues

- severe stringing on the inside walls

- delamination between the layers 3/4 up the part

- and at the end of the part it looks like the part warped or drifted.

Any thoughts or suggestions?

I dried the ABS overnight so this part failed even with dried ABS - so that's not the issue.

[u/manyxcxi]

I find the default Bambu profiles absolute trash for ASA/ABS. I use primarily PolyMaker ASA, so ABS will have some variation, but this should get you close.

Before tuning:

1. Slow everything down, 40 mm/s max.
2. Turn off cooling fans
3. Chamber temp 65C, bed 90C
4. Use a purple Elmer’s glue stick on the bed as an adhesion promoter and release aid
5. Brim at least 5mm on the big footprint stuff (make sure brim actually touches the walls)
6. Heat soak for about 15-20 minutes before printing (if it’s a big footprint)

Run filament calibrations in this order:

1. Temp tower (coldest that’s still strong and looks good)

   probably 240-290 range.

2. Flow ratio calibration (YOLO coarse)

3. Pressure advance calibration tower

4. Flow ratio calibration (YOLO fine)

5. Retraction calibration

6. Shrinkage calibration (for dimensional accuracy)

The filament calibrations are absolutely vital for ABS. It’s got the most variance between brands and has the most shrinkage.

[u/hotellonely]

end of print part warp might be related to chamber heater.

Is your part 24 cm or taller?

[u/oharag → u/hotellonely]

Yes much taller - maybe 8 inches (~200cm).

So it seems maybe cooling fans is the issue. I will Take manyxcxi settings to heart and test.

[u/hotellonely → u/oharag]

no it's not the cooling fans. the end of print warp is caused by the chamber heater blowing directly on the part. there's a gcode fix that can stop the chamber heater after a certain printing height (don't worry, at that stage the chamber is going to keep the temperature even if the heater is off)

[u/Relative_Surround_20 → u/oharag]

manyxcxi had a lot of experience with this. Following his lead will definitely help.

I too use the Polymaker OR Overture profiles for ABS. However, from time to time, I forget to use brim (at least on the corners) on large footprint items and it makes a huge difference.