Chipped filament is great but Bambu does not supply all the filaments or colors you might like or need.
That’s when you might find out that the generic profile isn’t producing as good as you might expect.
Fine tuning is required for the unknown filament.
If it comes with the required temp range, density and such you have it a bit easier.
Without a stated density try to stick with the default value.
Bambu studio makes setting up things quite easy in some areas but quite complicated or near impossible in others.
Have to write a story one day on how to get automatic supports placed where needed…
For a new filament and good results you need to consider two main factors:
- The flow ratio setting in the filament profile
- The max volumetric flow rate at the bottom
Why two different settings for the same thing?
The first is for an accurate extrusion volume to get the CORRECT widths for an extruded line.
The second limits the max speed based on how much the extruder can heat it and the nozzle get it out.
To set the first you need to print some cube or such in VASE mode.
Measure the wall thickness and compare it to your slicing values.
The default is 0.42mm
If it is less you need a higher flow ratio, it is more you need to reduce it.
To spare you a lot of prints and time there is a way to calculate this:
Let’s say you use standard values…
You should have a wall thickness of 0.42mm and a good finish.
You flow ratio is the default 0.98.
You actual wall thickness is just 0.39mm on average.
Divide the 0.98 by the real extrusion width of 0.39.
Them multiply with the width you require - 0.42.
Gives you a new flow ratio of 1.055 and should result in exactly 0.42mm for the thickness.
Same story if the wall is too thick, like being 0.46mm
0.98 divided by 0.46 then multiplied by the 0.42 gives you a flow ratio of 0.895.
With that out of the way we might have to check the temperature.
This is vital for filaments that should produce a glossy or transparent result.
Like before use the filament saving vase mode here and set lower temps every 2mm or so.
Stop the print once it starts to fail.
Where you can’t pull the layers (I know there is none in vase mode!) apart the temp is still high enough.
Add about 0.5 degrees to this value to have the lowest allowed print temperature.
The highest possible temp depends on factors like size of the printed are, how complex it is and so on.
Print one of these all in models to check overhangs, bridging and fine details in a single model - plenty out there !
The Benchy is great but for a beginner hard to interpret - much easier to use a dedicated model.
The BEST temp is the one where the bridging works fine AND where fine details neither cause a blob nor the thin stem that was printed to go soft and wobbly.
You can then create different profiles depending on the needs of your model.
Like for simple and quick shapes a higher speed and temp while delicate object can benefit from a lower speed and slightly lower temps to get the best surface finish.
Speed is everything if you own one of these machines…
The max volumetric flow rate limits what speed you run - it is literally like a limit setting.
Thankfully there is a really good set of instructions and a downloadable file to print available!
Doing it manually would take quite some time and and tests…
https://www.printables.com/model/318350-bambu-slicer-max-flow-test-tower-for-x1c
I suggest to reduce the max the test determines once you measured the result by at least 0.5.
For example a result of 24.3 turns into 23.8 - make it 23.5 05 23 to be on the save side.
If you then dare you can measure the model again to compare with the print preview.
The layer height will give you the print speed used.
I find this quite useful to print at the max speed with the highest print mode of 164% speed.
If the test showed your filament is good for a max of 260mm/s:
164 divided by 260 then multiplied by 100 = 158.5 mm/s for the standard 100% setting.
So instead of getting a messy print when speeding things up during the print you will never go to high.
And for something more complex the standard speed will then work just fine without too much need of tweaking.
Happy printing!
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In case you wonder about this magical K-factor…
Some people think that the K-Factor fixes all your extrusion issues magically.
Thing is that without the above it just won’t work.
If you adjust it BEFORE doing all the above then you might get a good result for the calibration print, find the matching line and all - but your prints might still fail or look bad.
The K-Factor should always be the last thing you calibrate when setting up a new filament.
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As a newbie I just did it in the order they appear in Bambu Studio’s calibration tab, which is reversed. As if that was not enough, the Flow Rate screen even specifically says “After using Flow Dynamics Calibration, there might still be some extrusion issues (…)” which gave me further impression that the correct order would be PA first. Nowadays I do agree with what you say, but my bad habit is hard to break… Bambu should reverse them on the calibration screen and rewrite those confusing instructions!
I probably never saw a problem because I was mostly using Bambu’s filaments, which tend to have good defaults for flow afaik. On another note I’m still wondering what happens if I use Bambu filament but never calibrate PA: Is there a hidden default that isn’t showing? Or will it actually use “no PA” or a K of 0.00?
It seemed like that for me as well when I did a test, that it is better to do the flow dynamics (K) last, but I think at the time I saw some things suggesting to do the flow rate after the flow dynamics, so I just continued doing it that way.
Have other people found that it is better to do the flow dynamics last?
Firstly, define all the settings for your filament. To do this, create a new profile in Bambu-Studio. To do this, use a generic profile, for example, and save the profile with a new name. Then adjust all settings, min. temp. + max. temp. etc. Save the profile. Calibrate the filament using the saved profile. K-value last. If you change temperatures (there is more in the wiki) recalibrate the K-value.
I think I know where the confusion is coming from…
In order to get good prints certain values need to match.
But, FROM THE OLD days we are used to do this in a certain order.
Bambu printers however are mostly automated for all this manual work.
Let’s say you have new filament with more or less unknown values.
The bed calibration is automated, so no user errors here.
The first layer is most vital - so you need the matching flow rate.
Without that all following layers are out of specs.
So we do the extrusion test with a single wall cube or something in vase mode.
Preferably the later because it elimitates the issues with non matching K-values!
Let me try to explain:
The K- Value mainly defines the extrusion rate and pressure during MOVEMENT CHANGES - like when changing layers.
If you do the Bambu calibration test print first the result will be disappointing.
Similar story for finding the correct max flow rate.
BOTH rely on the correct extrusion values to begin with.
I mean: How can the volumetric flow be accurate if your extrusion width is not ? 
So trying to tune things needs a working order.
You can change this order of course but it might mean you tune your results based on not so perfect base lines.
Do a simple check to work out which way(s) work best:
Pick a filament you know did not work well ‘out of the box’.
Create new profile for it so you can can later compare it to what you worked out.
Start with the generic profile and ignore it all to jump right to the K testing.
You WILL get a clean line somewhere and do the right thing - set it as the value for the filament.
NOW do the usual test prints to hone the extrusion factor…
If you do this with simple, single wall objects instead of complex test prints the vase mode might still let you do this.
A single wall cube not so much as most likely the corners will end as a mess.
Since all your values are set correctly it means you are printing too fast for this filament and reduce the speeds until it matches and gives clean, accurate results…
Go ahead and check if a K test still gives you the same value now
Now try again the other way around…
Get an accurate extrusion width and flow ratio sorted.
Then double check for the print temp to see when those layer lines look best - vital for see through or silk filaments…
If you changed the temp much check the accuracy of the extrusion again.
NOW do the K print…
Do a little, yet complex test print with the generated profiles and compare the results.
The max volumetric flow rate is only relative as many things won’t printed at full speed anyway.
But if you want to push the limits it is vital to have this value set properly!
The available test prints for this won’t let you find proper values is the above is not well done - you will always end with a slower value.
Whichever way works best for your needs go for it and stick to it.
I just try to do it for new rolls without wasting too much time and filament.
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I don’t see why the sequence of flow rate, max flow rate, and pressure advance makes a big difference.
max flow rate test doesn’t depend on PA setting, because the speed is very uniform, so PA doesn’t have an effect.
PA test doesn’t depend on max flow rate hopefully. If flow rate runs into the limit during the PA test then I doubt that the test gives meaningful results.
Flow calibration is also not needed for the PA test. It doesn’t matter if the line is a bit wider or narrower during the test.
PA before flow makes some sense, because some flow tests that include corners, might be a little bit easier to evaluate. But it also isn’t necessary.
Flow calibration obviously doesn’t depend on max flow.
max flow in theory depends on flow calibration. Practically, flow is often within a few percent ±, while the max flow is not a very exact test, so even a deviation of 10% doesn’t hurt too much. Of course it still makes sense to do flow calibration first.
So, I usually do calibration in the order
Temperature → PA → Flow → Max Flow.
In addition, I also check speed (especially for PETG) which seems to be different than max flow. and I try to find minimum layer time, but that is a bit tricky.
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As said: Whatever works best is what one should do
As long as the prints come out good enough there is nothing to worry about how one reaches this goal.
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