I wasn’t having this issue, and then I updated to the latest Bambu Studio, and now it seems that before any print my H2D is doing auto bed leveling 2 or 3 times.
I thought maybe it was a one-off but it’s doing it every print now.
Am I the only one seeing this? Any idea why it’s doing this?
I have seen mine do that sometimes for dual nozzle prints (not always?). I have yet to see it triple check the bed level for a single nozzle.
I suspected it was running 3 times because the values it got back were out of an expected range? Or maybe its not quite that complex.
This is definitely happening on single-nozzle prints.
It wasn’t doing it before updating Bambu Studio - but I’m not sure why that would affect it as I would think the bed leveling would be a part of the firmware - the H2D is on the latest firmware as well.
I watched paying more attention this time - it’s doing the full high-detail bed level, then it probes 5 points - front left, front right, middle, back left, back right, then it does the whole high-detail bed level all over again, then it starts printing. At least this time.
Last print it did all of that twice.
I am using a smooth PEI - when before I was using the textured - so maybe it’s just not liking the smooth plate? It’s an official Bambu one [and the prints coming off of it look great].
It is because the printer noticed the bed mesh has changed a lot (because of the change of plate) and it’s doing a recalibration.
Unless you do a full bed mesh calibration again (from the calibration menu), this behavior would happen a lot more frequent than you would like to. Also even though it tries to do a high precision calibration before print, the results would be very off sometimes when you’re printing something like a full plate artwork. The only solution is to still, do a full bed calibration if you change the nozzle, or plates. Especially if you’re chaging from a grained or textured plate to a smooth-ish plate, the difference is huge.
What I mean by ‘before I was using textured’ was that when I was using textured I didn’t notice this, and then I switched to smooth and now it’s doing it [nearly every time].
Just now I started my 8th print or so since I started this thread. I am doing a 2-nozzle print. I have been using the smooth plate non-stop since I put it on [so it’s not a difference between changing plates, at this point].
It did bed leveling on the right nozzle. Then it did bed leveling on the right nozzle again. Then it did bed leveling on the left nozzle. Then it did bed leveling on the left nozzle again.
I’m not sure why it’s doing bed leveling twice or three times per nozzle.
The bed level is done by load cell in contact with the plate itself - so it shouldn’t have any issues doing a bed level once for each nozzle, not twice.
I’ve just sat here for nearly 30 minutes while it was doing bed leveling over and over.
I stopped the print, and I’m now running through the full calibration suite in the settings to see if that helps.
I ran through the full suite of calibrations and my first dual-nozzle print after that looks to have bed leveled normally and not excessively.
Will keep paying attention to see if that changes. Then when I use textured next - I will watch for extra leveling.
I’ve noticed when I changed a plate and on a dual nozzle print that each nozzle will bed level at least 2 times each.
As I have stated, if the machine figures that the bed mesh result is crazy to it compared with the one stored from Machine Calibration bed mesh, then it would try probe again, and again, and then give up.
Since you have done machine calibration again, this time it stores the new bed mesh for your new plate & nozzle combination. As long as you don’t change this combination to something that is far different, the bed mesh should remain valid.
I’m not sure a machine calibration is actually required unless you have proof otherwise. I saw the multiple bed leveling occurring the first time or second time I switched plates but no longer am experiencing it. I am fairly certain the machine is saving and building a proper bed mesh from these pre-print bed leveling tests and not only when you perform a full calibration. I have only run that like once when I reset the machine as a test.
I could see it doing a double bed level after swapping a plate - but it was doing it on every print.
After running through the full calibration suite [although I probably only needed to do the bed level calibration] - it’s back to behaving as I expect.
I will pay attention next time I swap plates again - and see if it goes back to doing bed leveling over and over.
One of the things I really liked about this printer over my older Prusa’s is that the bed leveling was automatic as well as z-height [yes, I know modern Prusas are this way too] so I could just swap plates and not worry about air printing or driving the nozzle into the print sheet.
It will be very annoying if every time I change the plate I have to do the full bed level - especially since the printer can identify the type of plate on there - although I guess it can’t tell one textured plate from another, or one smooth from another [maybe some are thicker or thinner than others].
Either way - if the printer is doing 2x bed leveling because it detects something weird - [and not just the first print after changing plates] maybe it should say, ‘Hey, the bed level output is unusual - if you changed plates, please run the full calibration.’ or something.
Either way - next time I change plates - I’ll watch for this and update this thread. On my Prusa’s I preferred the textured and then the satin sheets because they ‘just worked’ but I do really like the smooth finish of a smooth plate.
So far I haven’t had one bed adhesion issue on the smooth PEI and I’ve been loving it.
Uhm, yes, it’s doing it for every print.
Bambu has a bed mesh MERGING algorithm. This merging algorithm I’m not familiar with as they never fully disclosed it, but the idea is very different from approaches that other firmwares (like klipper, and klipper adaptive mesh probing…). I think it initially started from the X1 series with the lidar, which is of course a different bed mesh system than probing. So how do you combine two different probing results, and how to generate a reliable bed mesh compensation? I guess that’s when they came up with this merging system.
For Klipper systems the newest bed mesh overwrites the previous one. But for Bambu, it would remember two sets of different bed meshes, one as a base model and the other one used to adapt to the current condition with minor adjustments. And for X1C they just use the lidar output as another mesh to merge with. I think Bambu found this method more reliable than other methods and in general practice it looks like to be the case.
Basically, the bed mesh that you did in the Machine Calibration has a much higher priority than the one you did before print. And it would be remembered.
Let’s call the Machine Calibration bed mesh “Base Bed Mesh”. The bed mesh before each print “Adjustment Bed Mesh” or “Adaptive Bed Mesh”.
ABM doesn’t “overwrite” your BBM. But it overwrites itself between each print.
Bambu uses the algorithm to merge your BBM with the ABM. But if the algorithm fails to merge them together, then it would try probe again. This time it would temporarily override the BBM as a failure back up. Or at least that’s what it seems to be doing. But the result can be very poor. So I’m not sure about this part (how it actually handles when it cannot merge the two bed meshes). All that I’m sure is that the BBM would only be overwritten with the Machine Calibration process.
Now, since you have changed a plate, your BBM no longer matches what it used to be. So a failure on merge is gonna happen, and because before print probing process only generates ABM and it would not overwrite the BBM, the next time you lunch a print it’s still gonna fail.
Fun fact: I miss the lidar on X1C. If you don’t swap plate on X1C, you can essentially turn off the abl probing before print and the lidar would take care of it 99% of the time.
I’ve changed plates several times after running the full calibration and it hasn’t reproduced this issue [multiple bed levels].
¯_(ツ)_/¯
When switching build plates, I always thoroughly wipe the bottom of the plate and the bed base to make sure no debris is caught between them.
A tiny crum of material is enough to locally lift your plate 0.05mm. Enough to get your mesh out of spec.
A full calibration would probably fix that, but the next print where the debris is gone, would render it out of spec again.
I have done the same.
One time I flipped a plate over and forgot to remove the purge line. Definitely understood why it was unhappy then.
But so far since doing the full calibration I’ve been unable to reproduce the original issue no matter how many times I swap the plates.
Hapenned the same to me almost im not alone
Just now, I think my H2D spent like 20mins auto bed leveling in a loop non-stop for both nozzle. Can’t even start a print…
I’m on Beta Bambu Studio and Beta firmware.
I’m on normal release firmware and I have also seen an increase in bed leveling times in the last couple weeks. I have only the one textured PEI plate, so no plate swaps. A print a few days ago (of course when my 4 y/o wanted to watch it print) must have done 10 minutes of bed leveling before it did anything else.
I know this doesn’t belong here, but is there a way to view the mesh map, or see the values?
Just updated the H2D today and it is now doing the multiple bed leveling before every print. Incredibly frustrating. Is the way to fix this to do a calibration?