I’ve had my H2D printer for a few weeks now and been extremely happy with the results so far, however I’ve just recieved and installed a pair of 0.2 nozzles and I’m having problems with running the pressure advance calibration with these installed, it works fine for the 0.4 nozzles but when the 0.2’s are installed the “manual” calibration results in lines with no discernable differences and the “automatic” calibration always fails after printing one line and suggests cleaning the build plate and trying again. I have cleaned the build plates (both textured and smooth) to no avail and tried with several different filaments but always get the same result. The printer recognises the nozzles correctly and I have run the auto calbration after the nozzle change.
Any help would be appreciated, many thanks.
Are you having issues with the prints? Seams? I find the stock settings + pre-print auto calibration work so well that I have not done any extra calibration for the filament with 0.2 nozzle or any others.
What plate are you using? I would try the smooth plate as it works better for auto calibration.
What filament are you using? Some CF and translucent filaments dont calibrate automatically very well.
Thanks for your reply.
I’ve used both textured and smooth plates with the same result, as for filament I’ve used a couple of different brands of PLA.
To be honest I’m getting quite good prints, perhaps a little over extrusion on the first couple of layers but I like to think I’m getting the most out of my printers and if the PA calibration tool is failing I wondered if there was something amis.
If it prints well, I would not bother with the PA/flow calibration. It was something that was required for good prints with P1/X1 but with the newer printers especially H2 series its not really needed unless there is a quality issue you are trying to solve.
I can confirm that the automatic calibration is both inaccurate and highly inconsistent. For my red ASA, the auto calibration may suggest 0.020, but in practice the actual sweet spot is 0.026. The same issue occurs with all other filaments I use. This may be related to the fact that I print with HF nozzles instead of standard ones, and at temperatures different from the stock settings.
What makes this even more problematic is the inconsistency: under the exact same conditions, the automatic calibration can return values anywhere between 0.020 and 0.070. For example, running the auto calibration three times in a row will produce three completely different results within that range—which is quite a significant deviation.
Even if prints look acceptable with stock settings, the resulting parts are far weaker compared to those produced with a properly fine-tuned profile. I haven’t tested this thoroughly with PLA yet, since I mostly use it as support material, but I could check that as well to see how much variation occurs.
So far, my observations apply only to 0.4 mm HF nozzles and the automatic calibration process, as I have not yet tested with 0.2 mm nozzles.
Fact box: How to detect incorrect PA using a 3–4 layer cube
Symptom: Seams and joints show small bulges or blobs
Likely cause: Too low PA/K-value
Symptom: Corners and line endings look rounded instead of sharp
Likely cause: Too low PA/K-value
Symptom: Surfaces look fine overall, but fine details lack crispness
Likely cause: Too low PA/K-value
Symptom: Small gaps appear between lines on walls
Likely cause: Too high PA/K-value
Symptom: Extrusion looks inconsistent or “starved” in infill and walls
Likely cause: Too high PA/K-value
Symptom: Corners are sharp, but walls are weaker and under-extruded
Likely cause: Too high PA/K-value
Fact box: How to detect incorrect Flow Ratio using a hollow 20×20×20 cube (no infill, no top layers)
Symptom: Walls measure thicker than expected with calipers
Likely cause: Flow Ratio too high
Symptom: Walls measure thinner than expected with calipers
Likely cause: Flow Ratio too low
Symptom: Surfaces look glossy and slightly “overstuffed” with ridges between lines
Likely cause: Flow Ratio too high
Symptom: Surfaces look matte or underfilled, with visible gaps/light passing through
Likely cause: Flow Ratio too low
Symptom: Corners bulge slightly even with correct PA values
Likely cause: Flow Ratio too high
Symptom: Layers have poor adhesion and can be separated by hand
Likely cause: Flow Ratio too low
But of course, it all depends on what you are aiming for—visual quality or functional strength.
Many thanks for that, at least I now know that it’s not just me.
I will experiment along the lines that you have outlined.
Hopefully this issue will be addressed in some future update but I won’t hold my breath on that one!
As I said earlier I have never run auto PA calibration on the H2D but on the X1 it was not very reliable either. I eventually gave up on auto and switched to manual.
The problem is that both flow ratio and pressure advance ¶ can vary across production batches and even between spools of the same color. If automatic calibration worked reliably, we would achieve consistently excellent prints. As it is, we must calibrate manually and monitor for defects that may arise from batch-to-batch variation.
Yes, you did say that. You also claimed the stock settings always work—but that’s clearly not the case, as plenty of forum reports show. If their automatic calibration worked as intended, we’d get excellent prints every time and could stick with stock settings without any drama.
Not exactly. I said they work for me and if OP is not seeing any problems in his prints then running the extra calibration can be redundant.
Yes, but we also need to be clear about what “works” really means — is it just appearance, or should it also have strength?
Some prints can look great on the outside but still be very weak. For example, I have some of my early ASA prints from the X1 Carbon that looked beautiful, but I could snap them with my fingers. The same model, after proper manual calibration, is much stronger and not so easy to break.
If the goal is only looks, then sure — anything that looks good is fine. But if it’s meant to last through normal use, it might be worth checking whether the filament needs calibration.
Let’s be specific about OP’s problem I’d say, .2 nozzle is unique.
.2 Auto calibration fail:
While A1/H2D’s auto calibration produces pretty useable results for .4/.6 nozzles, bambu wiki explicitly say it doesn’t work well for .2 nozzles. .2 Pre-print auto calibrations also tends to produce swollen corners so you are not seeing bugs.
Manual calibration for .2
This is an issue specific to .2 nozzles. Don’t use the manual ‘line’ method, it’ll produce drunken results, go straight to the ‘pattern’ method.
.2 nozzles typically produces much higher ‘optimal’ PA value than .4 nozzles. .4 PAs for filaments typically won’t exceed <0.04>, but .2 nozzles can reach upwards of <0.2> in values (PLA, PETGs). Prepare a boarder value range accordingly.
That said, .2 is tiny, don’t be surprised if line to line results are hard to tell apart, so pick whatever you felt is good enough, or use a high zoom macro lens cameras etc. I hate calibrating .2 for this very reason, but I’ll still do it for quality 
I also recommend that you check/calibrate flow rates again after manual PA is saved and applied, .2 nozzle prints are just pretty sensitive, I’ve found that manual PAs needs a new flow rate for best top surfaces. But once you do, it’ll be gorgeous.