The pressure advance setting, aka Factor K, was previously stored in the filament profile very close to the Flow Ratio number. That made sense, because AFAIK it is an attribute of a filament.
But now that location has disappeared entirely and has re-emerged in the AMS:
Can anyone explain why this makes sense? For instance, what if the spool of filament isn’t in an AMS, but is just sitting on the spool holder attached to the side of the printer?
Bump, I recently saw this in the slicer and thought the same thing. I was always under the impression that pressure advance is a per-filament setting.
AFAIK it gets saved to the printer. You can select a profile when on the Device tab. For example here I’m applying a previously saved profile to a spool that’s on the external spool holder.
I’m still running a version of Studio that pre-dates the security changes (so, 1.8 something maybe, too lazy to go look), and PA is set on the devices tab exactly as shown by the OP.
I think PA is handled by the printer, it’s not included in the slicer G-code. Which is why it’s there. Although I do admit to never really understanding why it’s not part of the Filament profile.
It’s always been on the AMS. Much consternation was had that firmware updates could obliterate it. Enough that I keep a separate spreadsheet for manually tuned filaments. The Bambu Studio/Orca profile version was provided as an override. Bambu lost it in early 2024(?) and will not respect the setting if you share Orca profiles with it.
FWIW, if you’ve saved your K factors elsewhere, and want to bring it back to the AMS, you can start a manual calibration, cancel it, and enter it back directly. You can also manage your results from the Calibration workflow (in either slicers). Kinda klunky - but I guess it simplified troubleshooting.
Oh, joy. I’ll keep a copy in the filament notes section then.
I already have so many profiles that I’m constantly getting the warning that any more will only be stored locally and not uploaded to a cloud somewhere. I’m rather surprised, as I thought storage space was cheap. Go figure.
I don’t remember exactly how to get there, but it’s not hard to find. There’s a popup window that lists all the K factors you’ve created on your printer. In that window, there’s a button to create a new profile. You click that and enter your value directly. Done. No need to do the calibration fake out…
This is handled much better by Orca, in the filament profiles. That was one of the main reasons I was using Orca with my X1 and P1. The other reason was “make overhangs printable” option.
Good news! I found out there’s an even better solution now, using the H2D automatic calibration prior to launching a print, that arguably far better in the H2D than whatever came before in any of the other Bambulab printers. Details and further explanation here:
The problem is we dont yet know how accurate it is. With X1 the auto calibration for PA left a lot to be desired especially with CF/GF filaments, not even mentioning TPU. Doing it manually always worked much better, I would prefer if they had it in the filament profiles like Orca.
You raise a good point, especially at the present time before the 10% jitter issue gets solved. Is there a good test print, preferably short and expedient, for monitoring how good a job it’s doing prior to launching a print, at least until we develop some degree of confidence in it? I like the idea that the automatic version can run before each print, given what the supportassistant said about the need to possibly adjust it somewhat based on filament moisture or other factors. Doing that work manually every time would get tedious in a hurry. Nonetheless, it would obviously only be awesome to the degree that it does a good job.
You could add a small cube and check the seam position, something along those lines (pun intended). 
If you find specific calibration issues generated by the printer, it would be a good idea to open a ticket, and share the log file from the machine including details for the exact filament used.
That way, our team can look into it to see what happened, what was the result, and work on further improving the results.
@SupportAssistant Again, thanks for your post. Since you’re following the discussion, would you please recommend an expedient model for us to test print that can provide some kind of easily quantized check on the quality of the H2D’s automatic k-factor measurement? That would be a win-win, in that it would help us to develop confidence in the quality of the automatic measurement, and it could potentially help you if we spot any issues to bring them to your attention more quickly. Maybe something similar to the “pattern” pressure advantage calibration test on the X1C, if that could be made to work on the H2D, since it can give a number accurate to a resolution of 0.001? Or if you know of anything better, we would surely welcome that as well.
Yesterday I did a complete manual PA calibration of PLA Basic white (granted, not the most difficult material) using the pattern type. After two test prints I ended up with 0.030. I then auto calibrated two other PLA Basic filaments (blue and black) and it gave me 0.029 and 0.030 respectively so at least for PLA it seems like it’s not worth doing the manual calibration. As for the Flow Rate calibration, the default 0.98 was pretty much spot on.
Yes for most materials the stock setting are pretty spot on. Its needed more for Nylon, TPU of CF materials that have a non-standard flow.
I’ll do the same comparison as before, do both a manual and auto calibration and see how close (or far) they end up being from each other. But it does seem like the use of their custom servo is indeed helping to improve the auto calibration. And according to Dr. Tao they want to dynamically change this value during printing, so it will only get better as time progresses.
