Out of curiosity, did you try again with the standard .4 hot ends that came with it?
I don’t see anything as bad as this with basic PLA with Bambu hot ends, but that could just be my machine is fine.
I did however do the hot end screw tightening (which you’ve done), I also did the belt tightening procedure just in case.
Same result with both the stock hotend and the HF ones I got from AliExpress. I’ve now done the belt tensioning for the first time (yes, I hadn’t done it yet — I’ve only had the machine for a short time), recalibrated everything, including the Vision encoder, and I’m trying again. Fingers crossed.
Please let me know mate, this can be useful
Good to know the hot ends aren’t to blame, AliExpress either has some total gems, or some total garbage at times! 
Best of luck post belt tighten
Tried reprinting the same model after tightening the belts and recalibrating everything — same defects as before. I also tried printing using both the left and right hotend — same issues.
At this point, if it’s a hardware problem, it might be related to the Z axis or the extruder (something not rotating perfectly on axis, causing inconsistent extrusion). Otherwise, it could be a slicer issue — but if that were the case, I’d expect everyone to be affected…
Doing a calibration and ticking the high-temp calibration option (not ticked by default) seems to have cleared up my Z-banding. It wasn’t bad for me anyway but I read in this thread someone recommending it, so I gave it a go. I don’t print high temp filaments and it still helped.
I am trying to print your model, it’s not finished yet but looks quite good so far. That’s BL PLA basic all preset default.
You tried everything but have you tried this (it may seem unrelated but it helped me)
Great print! Thanks for your input. Yes, I’ve already loosened that screw because I did the bed tramming.
OK so you have a lemon… I would have thought you could have what I experienced, the loosening of the extruder gear from the extruder wheel but it would give you extreme underextrusion which does not show in your print.
Edit: I can’t really tell but enlarging your picture seems to show some, you may just be at the early phase of the extruder failing
When you did the belt tensionning, have you noticed if your belt was running at an angle to the pulleys? I hade this on mine and loosened both tensionners to fix, I moved the printhead all over the bed to balance the tension before tightening the 4 screws. My belts are now running almost perpendicular to the pulleys (I still have a very small angle). Just asking because on your screenshot it seems the bottom of the belt on the right is grey rather than black indicating it might run against the pulley flange (but that may be just an optical illusion).
Looking at my X1C, all the belts are misaligned, but it prints beautifully. Anyway, I’ll redo the belt tensioning one more time — though honestly, I don’t have much hope. — thanks a lot for the suggestion, my friend!
I’d also like to add this — I don’t know if it’s related to the same issue, but I constantly get slight under-extrusion on the first layer. It’s minor, but unlike my X1Cs, where the first layer is absolutely perfect (almost looks ironed), on the H2D I always see a slight gap between the diagonal infill lines of the first layer.
Maybe it’s all tied to poor auto-calibration by the machine?
If you have underextrusion it might be your extruder. Mine started like this but I did not think too much about it until it failed for good. I was only printing engineering stuff from the time it started failing until it came dead so did not mind the quality of the prints and did not bother tweaking the profile but looking at those prints now they are not that great…
I had a topic here:
