I keep getting terrible quality on top layers, ever since I got the H2D - every filament I try (all PLA, currently). I’ve also tried many other things, such as reducing the flow from 0.98 to 0.90 or so, different nozzle temps, less outline overlap, faster/slower, different fan settings, different hot ends. I’m pretty much using default settings in bambu studio. I’m using 95% infill on this model (I avoid 100% on purpose). I think the nozzle is grinding on previous layers a bit? Some models print totally fine with the same filament and settings. Nothing I change seems to help. I just get different weird patterns if anything. Any idea what is happening?
Also, I’m getting random overextrusion it looks like on many models, such as toward the bottom of this one, even when I dial down the flow. Or does that flow setting not do anything if I have automatic flow calibration on? Also there are often weird bands on the sides of my models, like in these pics. There isn’t even a feature in the model that matches up. Seems strange?
Oh cool, it seems I figured it out! I thought the H2D was supposed to adjust the flow automatically, but I guess not, or not well. From the Calibration menu in bambu studio (which was hidden in past versions), I did the automatic flow dynamics calibration, and then manual calibration (which came out the same), then I did the manual flow rate calibration, and the problem is gone! I guess I should have tried that sooner, but I had read previously, multiple times, that these calibrations are not necessary on the H2D, and that’s why the Calibration menu was hidden. Obviously that was wrong. I had to set the PA Profile/Factor K on the Devices tab → AMS Materials Settings. I think it was the Flow Dynamics calibration that fixed the issue, not Flow Rate.
That’s correct. It was at 0.98 to start, then I tried 0.95, then 0.90, and the pattern changed, but that didn’t fix it. Seems the Flow Dynamics Calibration was the issue. Actually I’m reading about it now to understand it better. Flow Dynamics Calibration | Bambu Lab Wiki
Not sure why it was so far off. I think that makes sense though, since some areas printed ok, while areas in the middle did not… since the flow was changing while accel/decel - the overall flow was correct though. That probably also explains why smaller parts printed well, or even some large parts, depending on the orientation/length of the lines.
Yeah I always was leaving Flow Dynamics Calibration on when I goto print, which is why I didn’t bother trying to calibrate it manually in the past. But, clearly it doesn’t work, I guess. So, definitely keep it in mind if your prints aren’t coming out how you want. For me, it was mainly large horizontal surfaces. Not ideal though, since it was supposed to calibrate on-the-fly, but now I’d have to manually calibrate each filament/spool if I want the best quality. My hardware looks fine, visually. Not sure how I would check it. Also, I change hotends and that doesn’t fix the problem, proving it’s not a worn out nozzle.
The measurement of PLA Flow Dynamics shouldn’t be that bad. PLA’s PA values are highly linear in suitable printing temps, they VERY VERY BARELY CHANGES. There’s literally no reason for it to be as bad as you’ve shown here.
If it does, it means there’s something physically wrong with your printer.
I am having similar issues with top layer quality, see attached pics, the second shows the same test piece next to the best results from both steps of the flow rate calibration. I have also performed flow dynamics calibrations.
Any ideas on what causes the weird striations on the test piece would be greatly appreciated.
my guess for that picture is 1 or both of: whatever filament you are running does NOT like going that fast at that temperature, or pressure advance is turned off/really far out.
Re-do your pressure advance calibration, Reduce speed (of top surface, or in general), increase nozzle temp, etc.
