Calibration is the key to success.
If you don’t think so then just ignore the rest.
In case you do want to try to get better results just try to read and understand the following…
Make a coffee first or grab some snacks...
In the forum I can find a long list of topics where someone asks for help with z-banding issues, walls looking thicker where the bottom of the print ends and such.
While some of these issues come down to how the slicer works and what the machine is capable of, you CAN get near perfect results…
I am an advocate of calibrating what can be calibrated - be it the belts, pulleys or just print settings…
As so many I not just ordered a Bambu printer, I also took the offer to include a few rolls of filament.
Let’s not talk about those RF ID tags and the benefits…
What I noticed right away was that certain things did not print as expected.
Quite a bummer, considering how Bambu advertise(d) that all you need is a model and filament to get great results.
Anyway…
On my other (older) printers I always calibrated the filament and print settings to match.
One profile to fast prints, one for general use, one to get the best possible results even if it takes longer.
My P1S should have made this obsolete but I found out it did not, not even close.
So what actually is there that the user can take control over and calibrate ???
Extrusion and bed temperatures come to mind.
The first should be low enough so that there is no stringing but high enough to provide a proper layer bond even during faster print moves.
The second usually just means if you are way off the print will fail because it lifted off the bed or in the rare other extreme because you fused PETG, Nylon or such permanently to the bed.
So we can say these two are easy to address and easy to get right.
What about the flow ratio, max flow rate and the dubious k-factor ?
The k-factor is Bambu’s interpretation of pressure advance handling.
Meaning, the value we define determines how and when the printer pushes the filament faster or slower to ensure a proper extrusion.
The flow ratio is the thing that makes sure that the CORRECT amount of filament is extruded in general.
The max fow rate is used by Bambu more or less as a limiting factor that influences the print speed.
Let’s start with the last, the max flow rate…
The value we get from test prints or by trail and error is still RELATIVE.
Keep in mind that in an ideal world we would print with a constant FLOW RATE as this ensures the least amount of variation.
My E3D hotend has no issues pumping out PLA at over 40 for the max flow rate…
Does not mean though this value is usable in all cases…
What you really want to get from your max flow rate is COMBINED INFILL at the default print settings.
Default here meaning YOUR defaults as a high flow hotend needs some adjustments,
For the Bambu standard hotends the moderate 19 is a GOOD value as the hotend is not up for much more - being a bit restrictive and such.
Whatever value you establish as the max here - use about 20% LESS in your print settings to be on the safe side.
Now for the flow ratio…
As it suggests we set a value that shall give the perfect extrusion rate.
But what is this perfect rate???
If you do a lot of vase mode prints it makes sense to have a dedicated filament profile or k-factor for it now that the firmware and Studio support having them organised.
In vase mode you calibrate to get the set wall width.
If you set this to 0.6mm and the measure widths is just 0.52mm you need to increase the flow ratio accordingly.
Set flow ratio divided by the measured width then multiplied by the set width - easy enough 
For normal prints the requirements and procedures are a bit more complex…
Studio lets you print these 9 patches to check which one has the best top surface.
Makes sense to do both rounds here…
If you ever tried this with translucent filaments you probably already know that it can be tricky at times…
The key is to go for the surface that shows neither a gap between the lines NOR and build up between them.
For those see through filaments you can cheat by using a black permanent marker with a good tip.
Draw 90 degrees to the infill pattern and keep the tip steady - you don’t need to cover the entire patch…
K-factor or pressure advance in most slicer - what’s that ???
In lame words it defines who the extruder has to speed up or slow down during print moves.
When the line turns into a curve it means the extrusion result differs - the radius of the bend…
If there is a hard turn we need to slow down AND need to change the extruder speed to match…
You see that a little off for the k-factor can mean disaster if you print in very thin layers…
During normal prints it might result is ugly looking seems, bad layer adhesion in tight corners, too much extrusion in corners or in some cases a failed part of your print…
You can imagine now that both the k-factor and your extrusion rate being a bit off can mean the print is way off in some areas…
Means we calibrate the k-factor after the flow ratio and every time we change it.
Try to make use for the new features to store different k-factors for the same sort of filament as this way you can have several to cover even those 0.8mm layer prints…
The line pattern is not a bad start but for some plates the pattern is better, especially for those holo plates…
For the line pattern you want the one that is evenly throughout.
Above you have the gaps, below the bulging in the joint area.
Pick the best looking one.
Similar for the pattern.
To the top you have the corners bulging, at the bottom you find gaps between the lines.
The corner that looks the cleanest and sharpest is the one you want.
For both tests it can help to do another round to properly tune in to the best result.
Ok, you are not sure if it is worth your time and all the hassles…
Does the Benchy print FLAWLESS ?
Can you print a standard cube with sharp corners and no visible seam ?
Do those supports come off as planned or do you struggle ???
What about the box/window problem ?
Can you see on the outside of your box where the bottom ended or do the walls around a window in a wall look as if they got thicker or thinner for no reason?
All those problems go away once the filament is calibrated properly and you matched your print settings
Special case - high flow hotends or those hardened ones for abrasive filaments…
It can can be very tempting to drive those hardened hotends to their max when printing CF, GF or glow/filled filaments…
After all, we do have a fast printer …
Problem is that these filaments usually are rather restrictive and the hotends can be as well.
Getting the calibration order right here can be vital as otherwise you might waste a lot of money on failed prints or spend a lot of time finishing off the printed model.
Forget about the max flow rate here - at least until all the rest is sorted and then use it as a limiting factor.
Print temp, flow ratio, k-factor.
After this check what print speeds are possible by using the worst case, like bad overhangs and fine details.
You want to tune these properly and that means staying of the safe side of things.
Start with those overhangs and pay attention to the cooling and slowing down options in the profiles.
Then do the normal walls and single layer infill speeds.
Opt for the cleanest result not for what looks like it could barely make it …
Now check if the combined infill actually works…
Not all infill patterns are a good here.
Honeycomb for example shall provide a good match all the time, with the grid or triangle could result in gaps between the layers as some patterns are not equal in both print directions.
When trying to increase the max flow rate you need to pay attention to the other print speeds as the max flow rate is used in Studio as a limiting factor.
Meaning that an increase might result in inner walls and such to suddenly print MUCH faster.
Ask yourself here how important the fastest print speed is …
Once you increase the max flow rate you might find that the SET print speeds for walls or infill are LOWER than what the print preview shows…
This can cause severe troubles if you overlook it when it comes to things like corners and overall accuracy.
For filaments that SHOULD be printed slow you really need to be careful and pay attention…
High flow hotends anyone ?
If you upgraded the hotend to something less restrictive you are suddenly facing the issue that these test prints for the max flow rate will just complete without flaws…
So either opt for one that is made for these hotends or modify the normal ones to start with a faster print sprint speed - in line with model…
Best is to just start below the max of the model and that to match the layers.
Usually you measure the height where the print fails, so you want an even number here like 10 or 20mm to add to the result to give the matching max flow rate.
Maybe a bit easier for some is to just check how fast a combined solid infill works out.
Simply click the button for ludicrous mode…
If that gives a good infill you know that adding 66 percent will work just fine.
Then just repeat the print of the simple cube or cylinder with 66 percent added for the infill speed and click through the speeds until it fails…
ALWAYS keep in mind that being able to print insanely fast does not have to mean to actually works…
The part cooling fan will be your new beast friend so please do include it in your tuning …
You will not be able to overcome physics here!
While most of your model might have no issues being printed very fast because the layer time is high enough, some details will struggle…
PETG or Nylon can be very tricky here as the filament is more like a blob when it comes out during tiny print moves - bonding to the lower layer might not work as planned if you go too fast.
You always need to calibrate for the worst case in terms of slowest print speed.
Only what can be printed very fast should be printed fast
I try to keep several print profiles to cater for various model needs.
And I often end with additional profiles for lower layer heights as here the calibration requirements go up while the layer height goes down.