X2D horrible top layers

[Decamark]

Received my X2D almost 2 weeks ago, since then I haven’t been able to properly calibrate ONE of my spools, no matter what I do the top layer always comes out with ann horrible crisscross pattern that’s typical of the underextrusion symptoms…except that it happens even at 1.05 flow rate with the very same spool that on the A1 mini printed perfectly at 0.983 flow ratio. Yesterday I even dried the filament a bit more (12hrs at 55c) since with the first batch of tests I saw some oozing.

For this test I’m using Anycubic’s Basic PLA

But what are talking about exactly?

THIS

This is a shrinkage test block, no edits done to it, straight from makerworld.
Bottom piece is from the A1 mini, see how the lines are straight, proper and catch the light the same way?

Now look at the top piece from the X2D, mind you after rounds of flow calibration I landed at 0.975 which seemed to be a good choice, and yet it looks like a piece of yarn, irregular lines full of little pock marks, at a distance it doesn’t look that different but the moment light gets onto it you instantly can tell the difference

What did I do to try to solve this?

• dried filament
• re calibrated printer
• blow air into the extruder gear
• swap the nozzles around
• change flow
• change z offset
• print with the door open
• print with the aux fans all the way off
• 6 levels of top layers
• increase infill all the way to 35%, no difference between gyroid or normal one
• change filament, originally I was calibrating SUNLU’s pla+ 2.0, still had the same problem
• give a quarter turn more on the extruder tension screw
• checked the 3 screws behind the nozzle, the 4 small ones are locked in with loctite and didn’t move at all
• print with default PA and calibrated PA

Some more pics from other filament types

Anycubic pla+ it’s very matte, ignore the edges, those were due to improper PA at the time

X2D

A1M

Sunlu PLA+ 2.0, the square is the test piece on the X2D while the printed part under it is a previous print from the mini, you can sort of see the same effect on the Mini part, but only before walls, afterwards it’s a straight line

Lastly a piece with 1.05 flow ratio af the Anycubic basic, I’d expect ridges bumps and what not but it’s just a little rough that is all

Anyone else experiencing this issue? I’m at my wit’s end especially since the return window is VERY close by, I’m not expecting perfection but you know I’m at least expecting the same quality as the previous printer…

[Decamark]

I also asked another person to reproduce my calibration chip on their H2D which should have the same exact extruder assmembly for the Main nozzle, and here it is, straight lines no pock marks, not even calibrated the filament

[Alex_vG]

Just one theory: Maybe it extrudes at too low a temperature and therefore underextrudes at higher speeds? You could rule that out by cutting all speeds in half. If that solves the issue, the temperature sensor might contact the heating directly instead of the nozzle, causing significant lower temperatures in the nozzle than it reads back.

As a side note, allow me to promote my shrinkage test model that I would ascribe higher precision and less material used
https://makerworld.com/en/models/803990-shrinkingtest-v4-1-by-alex_vg#profileId-744301
Have a look at extensive explanation in the description.

[JamboBambu]

I see similar results and you can see several other active threads here for bad quality.
It is interesting that sometimes in one object I can get some areas very smooth and flat and others with lots of under extrusion and roughness. Sometimes it is better with auto calibration, sometimes with manual.
For example:
Here the bottom flat area is very smooth on touch is like perfect. The top smaller flat areas are like paper sand on touch and with clear under extrusion here and there, and prickly edges. Just few layers above…

[Decamark]

So far with you I have 5 other people having this issue, even calibrating the flow doesn’t produce the straight lines that the older motor machine were producing. Either we are all unlucky and have a defective unit or something is wrong software side

[Decamark]

I’m already at 220C which is the upper limit for that filament, if anything I should be easily overextruding. The rippley/crosshatch effect also appears at 50 mm/s top layer speed. About the temp sensor wouldn’t that result in everything underextruded and not only the top layer?

[macieksraciek]

I’m having the exact same issues with X2D. Gaps between the lines on top layer. Can be helped with dynamic flow calibration to some degree.

See the two parts - one printed on X2D one on P1S with 3000 hours on it. Somehow P1S top layer quality is better!!! It’s shocking and very disappointing. I hope Bambu acknowledges the problem and have some solution in the pipeline.

The filament has been dried for 12 hours two times already, it didn’t make any difference. And the P1S never had any issue with it anyway. I don’t understand how a premium grade printer can have issues like this.

[macieksraciek]

More of the same

[Alex_vG]

@Decamark

About the temp sensor wouldn’t that result in everything underextruded and not only the top layer?

My idea was this:
As intended by BambuLab, you have a thermal chain and at each transition you loose a bit of temperature. E.g.
Heater (230°C) → Hotend (215°C) → Sensor (214°C). So the heater has to actually get hotter than the desired hotend temperature, especially when more filament moves through the hotend consuming heat.
When the sensor touches the heater directly, the actual hotend temperature might be far lower than intended.

When flow is really low, then
1.) the temperature drop (heater → hotend) will be lower because less heat is drawn away by the filament and
2.) the filament prints fine at lower temperatures when printed slow. “In the old days”, it was very common to print PLA at 190-200 °C for better overhangs and deliberately increase the temperature only when printing fast.

I would not only reduce top speed but also all other speeds. Typically when the layers below top are underextruded, you will get gaps at the top even when flow is perfect, because the top layer also fills the gaps in the layers below.

A different test you could do that would be even more indicative:
In Studio, when you enable developer mode in the settings, a new calibration menu appears above the regular menu bar. There you can find a max flow test. It is buried in a some submenu there, i think “others”. It is a quick and very informative test that gradually increases flow rate and let’s you determine at which speed first imperfections appear. For BBL basic PLA, I easily achieved 30 mm³/s. If something is wrong with your extrusion system, you will clearly see it here. I had set the options to:
min flow: 10 mm³/s
max flow: 30 mm³/s
step: 1 mm (or was it (mm3/s)/mm? )
Make sure, that you have selected the profile for the filament you want to test in profile slot 1.

Of course all that is just a theory / idea that might be worth investigating.

Just as a reference, I switched from X1C to X2D and I was seriously impressed by the improvement in quality. Especially outer walls are far more consistent and all VFAs gone. Top surfaces also are slightly better at the edges. I have the feeling, that automatic flow dynamic calibration is far more accurate.

So I’m convinced that your machine is somehow defective like apparently many other. Unfortunately it is not easy to track down. I wish you best luck in finding the issue and will think about other possible root causes.

[Decamark]

Well, my walls are like yours. Smooth and vfa free so there’s that. As for the max volumetric flow it’s already down from 18 to 12 mm³ but this happens with filaments that run at 22mm³ too.

Isn’t the automatic flow calibration the one for pressure advance and not flow rate?

[Alex_vG]

I think you misunderstood me.
The max flow calibration from that menu is intended to determine how fast you can go with flow rate. The result is what you then enter as max volumetric flow in your filament profiles (minus some safety margin).
So I suggest the opposite of limiting flow rate in the profile but instead find out, how much flow rate your hotend is capable of. If that is significantly less than my 30 mm³/s, you know, that the hotend isn’t properly melting the filament.

I found an older post where I suggested the same thing to somebody else with pictures of my flow rate test:

New problems with P2S

I have run the extrusion test and I’m seriously impressed with the new standard nozzles compared to the X1C. No idea, why I bought a HF nozzle (which I haven’t tested yet). I guess, you know the extrusion test, but just in case the steps I took: [grafik] [{EAE24C80-491D-4D1B-A1EF-B9133D19040B}] This is the result I got: [PXL_20260610_202555892] [PXL_20260610_202800593] When you do the same test, do you also have good extrusion up to the top?

[Decamark]

Will try that, start at 12 end at 30?

[Alex_vG]

I used 10 → 30, but anything in the ballpark will probably work

[Qjo]

Commenting to follow here too I finally got straight lines, but still getting that texture

[Decamark]

X2D PLA Print flow rate isn't isn't fine - or some other issue?

Started to have artifacts at about 22 mm³/sec, dialed back to 20 and I’m still having problems. The squiggly lines have been mitigated by a generous lubing of the X and Y axis rods but the printer is clearly extruding plastic not the right way. [IMG_5544] ^^this is what another user on Sunlu pla+ 2.0 gets on generic basic pla preset VV this is what I get [IMG_20260706_145940564]

Crossposting the results of the experiment

[Alex_vG]

Maybe you can check the actual nozzle temperature? E.g. borrow a thermal camera?

[Decamark]

I don’t know anyone that has one, honestly at this point I just wish for support to just replace the unit. The bambu experience should be plug and play with their filaments and 2 or 3 calibrations with third party ones. As of now it’s been 2 weeks of test prints and headaches and nothing that I do produces the same result 2 times, I can’t even have an actual control piece to test calibrations against since I can’t be sure the printer EVER extruded plastic the right way

[javako-prints]

I have exactly the same problem with my now 4 weeks old X2d.
Printing and printers are not new to me, started with an Ender 6 years ago, changed the design so it printed - for that time - quiet well, got a Prusa - hardly better for 4 x the price .

Than the world changed with a P1P and some time later a mini. Both printers I managed to get extreme well results, that well that a lately a customer of me who visited a far asked me : I saw that and that at the booth of some one, did you made that for him? I asked how did you now? The answer was: because of the print quality.
This just to explain that I normally know how to get good results from a printer

Than I decided to sell my P1p ( took 5 minutes) and buy a X2d, mainly for the easiness of using support material.
Well, That might be a mistake, or at least I regret that enormously.

The walls are reasonably fine, not noticeably better than I was used to, but that’s fine.
The top layers however are horrible. They are rough, with lines very visible, openings between lines, line connect very bad to the perimeter wall. Exactly like the pictures you showed here.

And whatever I tried (all those things mentioned in this topic and more), there is no improvement.

I have two new AMS2 systems, 1 for each nozzle, and both nozzles give the same result. Although I checked everything in both systems, that fact that each nozzle has it’s own AMS, it’s own extruder, and heating system etc, so the are totally independent, I can only conclude that the problem must be somewhere deeper in the printer.

I have not yet contacted Bambu yet, but may I ask you if you did in the mean time? I get the feeling as I understand that there a several guys more that report this problem ( and a lot of guys that does not seem to have problems) that there might be a batch of X2d’s that have a production fault?

[shadow_dio]

Been going through this with support, they think I might have a bad heat bed and want me to replace it. I have a thermal temp gun and saw it had colder and warmer spots. Set to 40c, I had some around 39.5 and some 41.5. I wonder if this is enough to cause these weird issues.

[Loren42]

Just some things to think about when making measurements…

Consider the accuracy of your instrument, which is different than the precision of the instrument’s readout. You can probably find that information in your owner’s manual.

Secondly, how the measurement was made may have an effect.

Third, no heat bed will be totally isotropic (that is, all points at the exact same temperature).

Lastly, how long was the bed at 40°C before the measurement was taken?