So I've been trying to make my 0,2 nozzle work for a week now.
And after a week of watching guides (thx dungeon and derp (Obscure)) and talking to chatbots to try to find logic in all of this here is my summary
Dry your filament,
Temp--------------
Is the most important point when calibrating for 0,2 nozzle
Temp towers are sort of useless and at best can show you approximate ranges for the filament.
K (Flow Dynamics)-------------------
Is actually the most important aspect as that is basically filament stability towards speed changes
Originally i assumed i should pick higher temp for better flow as nozzle creates more pressure and they looked a lil better on my tower
But from what i found out is that picking too high of a value or too low of a value for temp severely affects K (stability to compensate)
In my case on my 235 nozzle i had to push my K to 0.45 and any adjustment made to the flow would dramatically affect my print quality
So i made a new method to find best filament temp for pla
Basically using the same flow 0.98 and doing line tests for each of the temps to find the lowest k (Most stable temp)
It is also way faster than temp tower because in bambu it is like 20 min compared to temp tower in which each every layer takes about an hour (In that time you can check 3 temps and see which had the K value decrease) (You could also hone onto the exact degree if you wished)
Pattern test is basically useless as higher pressure accumulates on higher values and over spills in the lower pressure lines on the second and third passes creating chaos
Stability is extremely important as it is already 10x more sensetive than 0.4 nozzle and its VERY difficult to get a precise good result with margin of error on flow rate calibration
In my tests for bambu basic white i got
215 - 0.395
220 - 0.37
225 - 0.4
Therefore it will be easier to calibrate 220 unless you want to spend more time to pinpoint the exact best degree (Do note that on the line test there are visible speed changes near first quarter and at the last quarter and they have to be as uniform as it gets with middle line being same diameter and not thinned out compared to them BOTH)
Small note tho is that i noticed that you can scratch your nail on the underside of the temp tower to check if it strings and on 215 it seemed to be adhering better but im not sure if its worth enough switching to that temp
Flow rate-----------------------
After that we need to do a game of cat and mouse because the moment we calibrate flow rate the K will need to be adjusted again and again until we finally arrive at the optimal range
One thing of note about this test is that it is very hard to tell which of the plates is the smoothest but you can grab a coin or scalpel head and rub it to see which produces less sound
Afterwards try to go for the lowest result (number wise even if they are almost identical) as under extrusion is better than over extrusion (Aka the pressure will slowly build up on each tiny point of overextrusion and youll get a long solid pube on travels or a blob)
Also thing i noticed is that the numbers on the plates seem to be super thin and you can check the stability of the first layer by basically pulling on them to see which are stronger.
It seems to be smart to add some z hop and higher fillement pull as well to compensate for minor overflows in case they happen due to temp changes in your house or smth but im still experimenting with them
Basically that is the most important part and the rest if just to test that your initial layer is solid enough as it is the a good indicator of over or under extrusion (you can adjust you flow rate bit by bit instead of doing the whole calibration again) and afterwards choose one of the printing profiles as they all will be a mess if your filament over extrudes
The final point seems to be printing angle towers and messing with speeds but in still a little away from those and they seemed pretty goods in obscures profiles