Settings for support interface

Hi, I’ve had the X1C Combo now for a week or two. Very happy with the printer overall so far (switching from Prusa).

But right now I’m having an issue. The printed model is like a tower 20x20x100 mm with som parts sticking out and need support. Tried printing with PLA and Support W for PLA, and also PA-CF with support G for PA-CF. I only use the support material in the interface to reduce printing time. And the printed part breaks extremely (!!) easy in many layers, related to where the support interfacce layers was. Both PLA and PA-CF.

Using the profile “0,2mm Strength” and 0,4mm nozzle in both cases.

I see that the standard values of top Z and bottom Z distance is set to 0,2mm. Would it help setting these to zero maybe?

And also, the flushing volumes, shouldn’t this be automatically calculated when syncing the AMS to Bambu studio? The standard looks like this (this I used when printing the described model):

Flush standard

And if I hit “Autocalculate” it changes to this:
Flush auto

1 = PLA Basic
2 = Support W
3 = PA-CF
4 = Support G

Can this also contribute to the problem?


So far I have only used PLA to support PETG and vice versa (because it is dirt cheap and works) and I have experienced weakness in the printed model at heights where support interface was used.

IMO it is caused by support material contaminating and weaken the bonding of the print material. You need to flush a lot more volume of print material. Last time I tried I think about 3 times the default volume was OK. I think the calculated flushing volumes are just based on color relative contamination so not really relevant.

As for other settings using support interface I set Z top and Z bottom to 0, top and bottom interface layers to 1, top and bottom interface spacing to 0, and interface pattern to concentric (I use the softfever fork, the stock version might not have all those settings). Apart from less interface layers I don’t think they will make a difference to the model strength problem. They just give the best finish on the supported surfaces and minimize material swaps.


Thanks @froboz

After I posted this, the Bambustudio updated and the default settings for Z top and bottom changed to 0.
So I made a simple model to try this out, see pictures.

Made the flushing volumes autocalculated this time (factor 1) and Z top and bottom to 0. It made a really huge difference, the part came out really strong. Eventually it snapped in the same layer as the support layer but I really had to use some force. So maybe putting up the flush volume factor to 2 or more would help, but this is as strong as I need it right now.
Glad it works since this was one of the key features made me go from Prusa to Bambu :grinning:

I made a functional PETG part with very thin and narrow features at the same layer as support interface. After several iterations and experimenting for best strength I suggest to set flushing from PLA support to PETG to something like 650-700 to be safe. Even slightest contamination with PLA decimates layer adhesion. On other hand when switching from PETG to PLA support interface, 200-250 is more than sufficient as some contamination is totally harmless.

I see you have the purge tower on - you can make it larger to flush more out. Is the “Flush into object infill” box checked?

Awesome, thanks a lot. Do you have hints and tipps for me to use PETG for prints? Next week I will start my first solid “Shelf” made out PETG. I will consider your flush settings, when I use PLA as support. I currenlty print with 0.6 noozle only to get some speed. Once the first layer is fully printed, I change the mode to “Sport” to accelerate the print by 25%. Do you have any hints with PETG, 0.6 noozle, textured plate and 0.36mm layer? Which noozle and bed temps do you use for PETG?

Well one tip for PETG is keep it dry. Out of the box new in a vacuum bag with desiccant does not mean a filament is dry, a common misconception.

PETG , depending on brand and color can be very hydroscopic, which can screw up otherwise fine prints. It’s so easy to forget it when playing with temps, layers, etc. :slightly_smiling_face:

Nice article on moisture and different filaments -

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Oh I have a “wärmeschublade” in mein Kitchen. It drys filament excellently :smiley:

This is what I found: How to dry PETG?
I recommend drying your PETG at a temperature of 60C-65C for at least 4 hours.

To be on the sure side, I will dry it for 5 hours at 60C in my ktichen.

You don’t need to interfere to change speed during the print. It just multiplies speed set in slicer by 1.25. Just set 1st layer and other speed/acceleration settings in bambu studio correctly. I didn’t try 0.6mm nozzle. You certainly need to dry PETG filament unless it came in a silvery moisture barrier bag. Also I suggest getting some moisture barrier bags (you can roll the open and and use clothes peg to keep it sealed) and silicagel bags to store dried spools. Silicagel bags can be dried together with filament and reused.

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Can you post screenshots of the settings in the slicer? Thank you in advance.