Auto bed leveling doesn't see to be working for me

Is the auto bed leveling still not working? When I do auto leveling, save, print I see > 0.2mm difference across the bed, making large prints impossible to complete.

Honestly this is one of the huge marketing features they show over and over, disappointing it doesn’t even work.

thanks
david

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Same. Went with a glass build plate to fix that.

Is there a write-up somewhere that tells you have to do manual calibration?

I opted to stick a magnet sheet on the glass plate and use the same removable build plate. Same auto calibration that way.

Otherwise you just go into the touchscreen settings and turn off auto calibration. When you run calibration again you’ll manually slide the card under each point.

Although if everything is tram, you don’t need to do a calibration. The idea is the bed is flat. Bed levelling can be disabled at that point. I’d do that by resetting all of the calibration points in the controller to 0 using the M421 gcode command, setting the home offset using M206, and saving. Then never using the touchscreen again, except to load prints from storage.

would you mind sharing the glass and magnet sheet you bought? I just don’t see how the Marlin bed leveling feature works when the bed is non-planar. Marlins leveling premise is that the bed is planar, just tilted.

With updated bed leveling and more sample points they can fix this, but I have my doubts. I did file an “official” help ticket. We’ll see what happens.

thanks

Snapmaker Marlin uses the AUTO_BED_LEVELING_BILINEAR flag for a mesh with bilinear interpolation. Measure a grid, and for any point then to this: https://en.wikipedia.org/wiki/Bilinear_interpolation. I think you’re thinking of Marlin ABL (or UBL?) which is not used in Snapmaker’s firmware. More on that here and elsewhere in the Marlin docs: https://marlinfw.org/docs/gcode/G029-abl-bilinear.html. Don’t use G29 though, Snapmaker wraps it with G1029 that needs a setup call ahead of time - if you call G29 it won’t work right and may crash.

I went with a sheet of borosilicate that was close enough to the right size, although some glass cutters could cut a custom sheet for roughly the same price. I got the GO-3D 310x370mm plate - pre cut for a different printer and has mounting holes, but the holes were covered up by the sticker: https://www.th3dstudio.com/product/ezflex-magnetic-base/

Someone else on the forums found a glass cutter online and ordered a custom sized glass from here https://cgindustrialglass.com/industrial/ that was even thicker for more rigidity - I’d probably do that if I did it over.

I filed an official ticket with snapmaker. After a couple of email exchanges they are able to reproduce the issue.

I can move my print head to 0,0 and as the bed heats measure the warping as it is happening. It gets worst the higher the bed temperature. I’m now only printing PLA so I print at 35C, but still see some warping so I’m restricted to the central part of the print bed.

Supposedly this issue has been passed on to R&D to see if they can come up with a fix.

In the meantime I ordered a new steel PEI coated print bed, that I will put on top of a sheet of glass cut to fit. I’m not hopefully this warping issue will be addressed soon, though I see other people printing across the entire bed without issue.

I hope support is able to come up with something useful for you.

I’ve seen 2 methods of dealing with the bed heat induced warp

  1. Heat the bed up for 30 minutes or so, then quickly do a calibration while the bed is mostly at temperature.
  2. After calibration heat up the bed. Use a combination of G42 and M421 Q to tweak each mesh value so that it is level at temperture.

Method 2 would go something like Go to mesh I0 J0, at Z=1mm or something higher than would scrape the bed, slowly jog Z down so the card is correctly tensioned under the nozzle. Read the current Z value, and adjust the mesh at that point such that Z becomes 0. If Z=0.15 at I0 J0, you would issue M421 I0 J0 Q0.15 (or possibly negative, can’t remember)

I looked at method 2 and didn’t want to mess with it. I’d have to do it for the different temperatures for the different materials. Then I get frustrated because I spent the money on the Snapmaker so I didn’t have to play with it. If I wanted to continue playing I would keep printing on my other printer :slight_smile:

So I opted for a different print bed, with the steel lining I’m hoping auto-level will work.

Same. I think it’ll work. Good luck!

Any update on this? Did the steel print bed fix the isue?

I ended up using the bed visualization plugin in Octoprint and used paper shims to level the bed out. After doing that I have printed a lot of stuff successfully.

I filed a ticket with Snapmaker with the bed visualization results and they have shipped me a replacement that is supposed to be flat. Still waiting for it to arrive.

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You can also connect your computer to the SN, start the manual leveling procedures, but before you actually measure any points, use your computer to set the bed to the desired temp, then wait for it to heat and add some time for thermal expansion. Then continue measuring as normal, with a bed that is staying at temp for the duration. Warning! your print bed will be hot when you do this! (obviously, but I feel it needs to be pointed out)

That said, my mesh is still all over the place, and I absolutely have to babysit the first couple layers, but at least I am actually managing prints now. It’s incredibly frustrating that this issue that has been around for over a year still hasn’t been addressed. Ready to start mentioning it on ever FB ad I see.