X2D horrible top layers

Decamark · July 1, 2026, 10:01am

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 · July 1, 2026, 10:58am

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 · July 1, 2026, 4:14pm

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 · July 1, 2026, 6:00pm

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 · July 1, 2026, 10:30pm

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 · July 2, 2026, 1:12am

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 · July 2, 2026, 2:31am

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 · July 2, 2026, 5:37am

More of the same

Alex_vG · July 2, 2026, 7:07am

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.