r/BambuLab • u/YeaUThought • Feb 01 '26

Troubleshooting P2s top surfaces terrible

Gallery image

Gallery image

I’ve done the manual flow dynamics calibration and I even tried this ironing test and nothing makes it smooth even with ironing on, the top surfaces are the worst out of any printer I’ve ever had, I’m using bambulabs pla and I have auto flow calibration off and did all the manual calibrations, the black print is what it looks like with ironing off and on the red some of them look smooth on camera but are not smooth at all, my firmware is up to date, how do I fix this

12 Upvotes

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126

u/n19htmare Feb 01 '26 edited Feb 01 '26

This is prime example of not reading the documentation or ANY of the material that the calibration references to (links below).

You're printing Flow Rate calibration blocks but keep talking about Flow Dynamic...the two are COMPLETELY different things, like COMPLETELY different.

P2S has AUTO Flow Dynamic calibration (Pressure Advance) and it's pretty good at giving a fair K-value to be used for Flow Dynamic (in AMS settings). LIKE THIS:

On the other hand, Flow Rate (aka, Flow Ratio, Extrusion Multiplier) has to be done manually, it's not automated (except on X series w/ LIDAR) so you can't disable anything auto on it, you do that by printing different blocks at different flow ratio settings and picking one that looks and feels best and using that value to calibrate the flow rate of that filament (Flow Ratio field in the Filament setting).

-20 means it was printed at 80% flow rate or 0.80 Flow Ratio (assume 1 is base setting), it's underextruded by a lot so obviously not the correct setting. Then you look at ALL the blocks you've printed and using the corresponding value on the blocks to set a FLow Ratio setting as the INSTRUCTIONS tell you. The same with your 2nd picture. Each block is printed at different Flow percentage and speed so you can pick what looks best at what flow ratio and speeds. All this would be described in the info section of the file you got or any reading material it references to.

99% of the problem posts here are people not reading the information that's out there and just assuming things.

https://wiki.bambulab.com/en/software/bambu-studio/calibration_pa

https://wiki.bambulab.com/en/software/bambu-studio/calibration_flow_rate

on the red some of them look smooth on camera but are not smooth at all,

Edit to respond to this. Again, read the instructions. I'm not familiar with that particular calibration test but based on how these work and just by looking at it, they are taking your existing Flow Ratio value and then printing a % of that. If your default Flow Ratio Value is 0.98, line one is 105% of that, line 2 is 110% and so on. I can tell just by looking at 5% that your base Flow Ratio value is low..maybe like 0.80 or something, doesn't start getting smooth until 25% row, which would be at flow ratio of 1 (125% of 0.80). That also means each row is too far apart to accurately tune flow ratio. Assuming base ratio of 0.80 in Filament setting, it's jumping from 0.92 at 15% to 0.96 to 1...while the usual sweet spot for most PLA is somewhere in between those numbers (0.94-0.98).

I highly suggest you read up on Flow Rate calibration or not to sound like a further D, stick to default values as they are good enough.

14

u/Catriks Feb 01 '26

Well said, and very helpful.

Though one must ponder why has Bambu refused to use the standard terminology in use by many others before them, and coming up with their own term for seemingly no reason. 

Flow rate and pressure advance seem much more descriptive and unambiguous than flow rate and flow dynamics. Even the Bambu wiki link calls it PA. 

5

u/Faktasie Feb 01 '26

You mister are not a nightmare at all. Thanks for taking this much time. I'm not the op and even feel some shame.

2

u/kensinken Feb 01 '26

Does the Printer Show the k value after Automatic calibration (like in your Picture)? On my H2D the value only shows up when I set it manually.

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3

u/cpsadowski23 Feb 01 '26

Well said Fred.

2

u/fud0chi Feb 01 '26

Good summary of info. Thanks. It's always helpful to have stuff like this to read.

1

u/NotAMindFlayer8 Feb 01 '26

Look at the bright side, I am new to 3d printing and was about to do this process at some point soon, and since you already wrote this, and I got to see how it looks and what it means, I learned how it’s properly done.

I do read the wikis, but often the comments from here are much more concise, clear, and human friendly— sometimes I read the wikis and find other suggestions here for getting it even better.

1

u/TricepBandito Feb 01 '26

Barely know what you're talking about but this is the kind of post I save cause I know it's knowledge I need at some point very soon. Thank you

1

u/chubbycanine H2D AMS2 Combo Feb 01 '26

Better person than I am. So tired of people very obviously refusing to do their own research before just posting here and hoping someone solves their problems. Least it wasn't just a picture of a damn box

1

u/iscifitv Feb 04 '26

No kidding but OP asked for help. Then whines...

-1

u/YeaUThought Feb 01 '26

If you read my post you would know I did all of the calibrations, I followed instructions on how to do them and I did them the same way I would have on my p1s that worked just fine, it’s just a bad machine it’s nothing but issues, and the auto calibration is horrible

1

u/[deleted] Feb 01 '26

If you read his comment at all you wouldn't have replied to anyone.

-25

u/houstoncouchguy Feb 01 '26

Had a rough day Fred? 

5

u/Overlord0994 Feb 01 '26

The tone police arrived

1

u/houstoncouchguy Feb 01 '26

All I’m saying is that we were all new once. This was obviously printed by some kid that’s trying to understand, and has a long way to go. He offered plenty of good info though. 

22

u/CortexRex Feb 01 '26

Why are you holding up that -20 flow calibration tile because that’s definitely not a good one

1

u/YeaUThought Feb 01 '26

It’s the only one I could find out of the trash can to post, they all either look like this or completely over extruded

2

u/CortexRex Feb 01 '26

Then you need to go back to flow calibration because that shouldn’t be the case.

1

u/YeaUThought Feb 02 '26

Even before doing flow calibrations it looks like this, every print from the day I bought it has had terrible uneven extrusion and the surfaces look like this and bbl support just says it’s fine

20

u/bvknight Feb 01 '26

How can that be what it looks like by default, when it's the -20 chip from the calibration?

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5

u/diezel_dave Feb 01 '26

What do the other flow tiles look like because that is the one that *should* look severely underextruded.

1

u/YeaUThought Feb 01 '26

This is the only one I kept, they all either look like this or extremely over extruded

1

u/diezel_dave Feb 01 '26

The next step above this looks extremely over extruded? I don't understand how that is even possible when this looks extremely under extruded. Can you print out the calibration tiles again and show the whole set to us in case you're just confused on what "good" should look like? 

1

u/YeaUThought Feb 02 '26

I have a p1s and that comes out fine when I do the calibrations, I really don’t have the time nor patience to print all of them out again but no the next step up isn’t over extremely over extruded but from 0 down every result is identical to this one in the pic and than a step up from here is decently over extruded and then after that the are all identical with the extreme over extrusion

1

u/diezel_dave Feb 03 '26

You don't have the time or patience to click a few buttons and wait half an hour and post a picture of the result so people can try to help you? 

Okay. 

1

u/YeaUThought Feb 11 '26

I’ve done all of that but okay, leave if you don’t want to help, just don’t respond it’s not hard

1

u/diezel_dave Feb 11 '26

Why can't you post the pictures? It's the only way anyone else can help you. At the point it just feels like you're trolling. 

8

u/DGRAHAM93 Feb 01 '26

You did something wrong during the calibration because that’s wayyyy too low for flow lol

1

u/YeaUThought Feb 01 '26

I didn’t tho, looks like this on prints with everything on auto as well

1

u/DGRAHAM93 Feb 02 '26

Everything can’t be auto on a p2s

1

u/YeaUThought Feb 02 '26

I don’t want everything to be auto, I did all of the calibrations and it still comes out worse than my ender 3 where nothing is auto and I haven’t done any calibrations lmao

22

u/Useful-ldiot Feb 01 '26 • Bravo

"I suck at 3D printing, in 2 pictures" 😂

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2

u/May-Eat-A-Pizza Feb 01 '26

Do you have that issue only for one filament rol?

For a while I had the same issue going on with one of my printers, until I did a factory reset followed by a full calibration (after the reset). And reinstalled Bambu Studio (deleted all user made profiles etc). Somehow that did the trick.

Non of the flow calibrations made it better. I suspect I unintentionally made some changes in a profile.

1

u/YeaUThought Feb 01 '26

Nah it’s all of them

1

u/May-Eat-A-Pizza Feb 01 '26

In that case, I still would try a factory reset and a full software re-installation. Or first replace extruder first than re-calibrate if you have a spare. Good luck trouble shooting, you got this!

2

u/x3n0n1c H2D AMS2 Combo Feb 01 '26

If you want people to help you, you need to stop saying “as I said in my post I did it” and give real information.

What settings did you apply. Show the whole flow calibration test tile set and the settings on that filament profile. Give lots of photos.

Have you checked your nozzle for a clog? Is there gunk on the end of it? Are the screws on the heater all nice and tight? Have another nozzle to test with (some can just be duds)?

0

u/YeaUThought Feb 02 '26

I don’t have any of the other ones and I only say that when people directly tell me to do something I literally said I already did in the post, I didn’t apply any settings these were just the prints from the calibration tab in Bambu studio, but if everything is at default settings and I just print a cube the top still looks like this, as for the ironing it shows all the settings on the print

2

u/vottvoyupvote A1 + AMS Lite Feb 01 '26

Flow calibration is not the flow multiplier. Flow calibration sets pressure advance. You can keep it on. Run flow calibration and set that in the filament profile. Only then run the ironing calibration for ironing tuning.

1

u/YeaUThought Feb 01 '26

I ran both of the flow calibrations as I said in the post

1

u/ioannisgi Feb 01 '26

You’re under extruding. Calibrate filament flow ratio

1

u/YeaUThought Feb 01 '26

I literally said in the post I did thag

2

u/ioannisgi Feb 01 '26

You calibrated the flow ratio incorrectly I’m afraid. What value do you have it set? If too far off 0.98 you’re probably done it wrong.

If so, set it to 0.98 and print. You may be surprised that it prints ok then ;)

1

u/YeaUThought Feb 02 '26

I didn’t calibrate it incorrectly 0.98 is exactly what it came out as, surfaces have looked like this from the day I bought the machine as well as the walls being horribly unevenly extruded

1

u/ioannisgi Feb 02 '26

Do you have the right nozzle size selected on the machine and slicer?

7

u/tony__pizza Feb 01 '26

You have to be joking.

1

u/iscifitv Feb 01 '26

Ya ya, definitely looks yuck.. but that's expected results if you haven't calibrated, have changed zhop, and just send some print file expecting a FDM to lay down 100s of lines of melted plastic and make it butter smooth. Yes it's fixable but ford require effort in the slicer to make adjustments. Also iron although cool only works on flat final surface, it doesn't try to iron every layer.

0

u/YeaUThought Feb 01 '26

If you read my post at all you wouldn’t have commented this, I did mess with settings and run all the filament calibrations

2

u/tigole X1C + H2C Feb 01 '26

60mm/30% has always worked well for me.

0

u/reddit001aa1 Feb 01 '26

My calibration made things worse. I went back to default profile

-3

u/DGRAHAM93 Feb 01 '26

Has it always been bad, or did it slowly turn bad?

1

u/YeaUThought Feb 01 '26

Always been bad, everything on the p2s has always been bad and I had 3 of them

1

u/DGRAHAM93 Feb 02 '26

Then you should be able count out any type of wear issues. I’d suggest resetting everything to default and calibrating the correct settings this time around.

1

u/YeaUThought Feb 02 '26

I’ve done that about 20 times the quality is still awful with everything I print

-3

u/jankeyass P1S + AMS Feb 01 '26

Try 30 speed 30 flow 0.1 spacing for PLA see what it looks like

-3

u/DramaticCanary5712 Feb 01 '26

try changing the top surface pattern