Filament dynamic calibration factors

I must say I am a little confused with filament calibration.

When using AMS is the calibration result stored for the filament?
So if it is calibrated once I do not have to repeat calibration every time, even if printing with different filament from AMS in the meantime?

Also In the AMS setting for filament there is a section “factors for dynamic flow calibration”
But is behaves as it is not usable.
What is it for?


If you are doing automatic calibration and using the AMS, only the first filament used gets calibrated and this information is not saved. On the X1C, the interface does not allow you to enter the “flow dynanics” (pressure advance) K factor, but on the other printers it does. You can run flow rate and flow dynamics (two different things) calibration. Flow rate is saved to a user filament profile (this is a value Bambu Studio lets you set).

The printer can remember up to 30 flow dynamics K values, remembered for filament profiles it knows about (either system or custom ones you create). You’re then required to select the K factor from a dropdown list related to that profile. It’s a rather strange system. If you use OrcaSlicer, it lets you specify your own K value in the filament profile.

If you do save filament calibration, and are using an X1C, turn off automatic calibration when you start a print.

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How do I save filament calibration?

How do I get to know K value? Where can I read it?


You cannot save the automatic calibration done at the start of a print. Bambu Studio now lets you run automatic or manual calibration for flow rate and “flow dynamics” (pressure advance K value); you do this by clicking on the Calibration tab. Flow Rate Calibration | Bambu Lab Wiki and Flow Dynamics Calibration | Bambu Lab Wiki I recommend doing flow rate calibration first.

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Ok I did calibrate the filament in bambustudio.

But I do not get how do I use results of the calibration.

I have flow rate factor updated in filament preset, that’s easy to understand.

But I am not able to use K factor from dynamic calibration.

First time I did the calibration it did actually saved this value to printer and K factor was visible in the filament in AMS.
Bur second I clicked on the material in AMS to edit this value was lost and it is not possible to set it again.

How do I save calibration results for given filament to be able to use them later (for different spool, different slot in AMS, or just set it after I have removed and put filament back in AMS).


Also I have noticed that K value does not stay saved for filament in AMS slot after I switch off BambuStudio.
Just like it was never actually saved in AMS.


The AMS does not save anything.

Flow Dynamics Calibration | Bambu Lab Wiki explains the process and how to recall the saved K value - it’s a rather clunky system. If you use OrcaSlicer you can set the K value directly in the filament profile.

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It really is akward … and the fact that you may do a calibration and not realize it’s not saved anywhere.

I have a theory about why they did it this way, however. In the walled garden of bambu, where in theory every filament spool has a rfid, you only need to do the calibration for each type of filament, not each color * type * vendor * etc.

So, I could put a BBL matte, basic, tough, and silk into my AMS, press calibrate, and in theory the dozens of spools that I might have that match those will all magically be calibrated. And maybe I do this every month when conditions change in my workshop. It could make sense. But only if you are allllll in on BBL filament.

I have what I think is a better theory, which is a combination of two things. 1) Bambu is notably terrible at user interfaces, and 2) this was them shoehorning the feature into their existing infrastructure with the least effort. That they did it at all I am happy about, but the manner in which they exposed the feature is infuriating and user-unfriendly,

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I see that in Bambu Studio 1.9 Beta they have changed/improved the management of filament calibration factors. It will be interesting to test this and see if it is better.

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The theory is wrong. I’ve found that changing filament type, manufacturer, or color requires at least slightly different settings for best results. So I use OrcaSlicer, with a preset for every filament.

This. It is Bambu trying to implement printing from Makerworld through Handy without involving a slicer on a computer, and doing a poor job of it.

Bambu already has all my filament User Presets in their cloud - why not provide an option to use those settings instead of data that may or may not be on the printer? That would allow the use of any filament I’ve calibrated, from any manufacturer, with names I’m familiar with instead of these ridiculously long inherited names.

Even though Studio will not show the K value added to a User preset by OrcaSlicer, it will use it in the g-code sent to the printer, overriding the value shown on the Device tab. So, why not do the same for the Makerworld cloud slicer?

Since I never use the cloud slicer, I have no opinion on that part, but the current (production) UI for flow dynamics (K) settings is just horrible. I will be interested in seeing how the beta 1.9 version works.

Do keep in mind that one can also select filament profiles (and any saved flow dynamics settings) are also selectable on the printer, which further complicates the user interface (and also ties into the limit on how many user profiles you can set.)

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I encourage you to reread my message; no big deal, but your reply makes me think you’re misunderstanding me. :slight_smile:

My reply was poorly worded. It is the Bambu theory that I think is wrong, not yours.

My understanding is that Bambu thinks that all their colors of the same type can use the same settings. My limited experience with Bambu filament and more extensive experience with other brands tells me that different colors of the same type and manufacturer can require different settings.


Ahh, I see your point and appreciate your explanation.

My own experience has been that BBL PLA basic is actually reasonably stable across all colors, but needs recalibration when my room temp/humidity changes a great deal. Less so with 3rd party filaments.

getting back to basics.

I have calibration saved in BambuStudio but only thing I cand directly do with it is edit and delete.
There is no option to set this value to the printer, so it is assigned to filament loaded in AMS.

Currently to assign K value from this calibration to a filament in AMS I need to go throught:

  1. Manual calibration
  2. Cancel print calibration in printer
  3. Finish manual calibration despite canceling the actual print
  4. Set K value I already know.

What is the more easy way?


How do I set K value for filament in Orca Slicer?

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difference in names is obviously misleading.

Now another aspect.

I have installed orca slicer an tried it. Unfortunately it is not cross compatible with BambuStudio so I am not sure which one I will end up using.
My concern now is:

If I enable pressure advance in orca slicer and set this value manually for a filament it is tan updated and I can use the same filament in Bambu Studio.
In the same time I can have this calibrated in BambuStudio and K value may be set for the filament in the AMS through the filament profile set in printer.

Now in such situation which value is used when printing?
And further, which value is used when printing from Orca and Bambu Studio?


I’m not sure what incompatibility you are referring to, other than OrcaSlicer not being linked with MakerWorld. Studio is catching up with OrcaSlicer (by using Orca source code), but OrcaSlicer still has more useful features.

Both Studio and Orca will use the value saved by Orcaslicer in the User filament preset to create gcode for the printer, overriding any value shown on the Device tab.