Cant get front to back Z alignment

I have recalibrated a ton of times, changed the calibration matrix points, but consistently the front of my 16cm test square is high and the back is flattened.
I’m confused how so many calibrated points can produce this offset?
any help greatly appreciated, ive tried everything I can think of.
latest firmware/luban
video of result

What version of firmware are you running? The latest version is here:

The video is showing that your machine isn’t leveled if there is that much difference front to back. If everything is up-to-date, you might need to perform a full factory reset and reinstall the firmware.

I updated the firmware to the latest and sized up the test square. Same issue. I’ll look around for how to factory reset. Tried the tap 5 times trick for more options, no dice.

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I found the “Reset All” button buried in the dev panel and gave it a go. I then re updated the firmware to the latest. Same result.

Any other ideas?

You’ve probably already checked, but are you sure you haven’t made an error in assembling the machine? It wouldn’t be the first time that turned out to be at the root of someone’s weird bed-related issues.

Agreed. Share picture of your machine and it’s assembly.
From front at bed height for sure plus other angles.

Also, check that there isn’t any excess play in your linear module brackets especially for the bed. The bed should deflect with finger pressure but shouldn’t easily rock.

Are you using the 5x5 calibration?


I am doing 5x5. Here are some images, please request any other angle.
I’ll could take the bed apart but i dont see any strange play or screws loose. Also, this configuration was printing fine before, I think this showed up after a move.

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Google Photos

Thanks for the help!

When running the auto-level, does any part of the 3D Print Module touch the build surface at any time? You’ll need to watch every step of the auto-level with your eye level at the build plate, as you can’t see this from any other view. No part of the module should get closer than 1-2mm. You could also put a piece of paper under the module and follow it around, as the paper should not affect the measurements.

It wouldn’t be x-axis with the problems he’s having.

Assembly looks fine. None of the usual problems with upside down bed, wrong screws or y-rails over hanging.
You said you just moved the machine. Are the z-towers still perfectly vertical and sitting flush in their notches and perpendicular to the bed? They didn’t get bent/tilted back?


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I may be suffering from the same issue. I’ve noticed when watching the y-axis moves the build plate forward and backward that depending on the direction, the edge of the build plate will rise or fall. It’s as if the torque of the linear actuator is tilting the build plate.

This means that parts printed in the middle of the plate are fine, but the further to the edge, the more likely they are to not adhere.

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sounds like it might similar to my issues, where the up down movement on the y rails is enough to cause a variance in the first layer height of +0.2 mm in some parts of the build surface. Below is the post where folks helped me figure it out and confirm it. Plus the post of the test i was doing that made me realize i have issues.

Just starting here. Yes it penetrates pretty deep in the back right and less towards the front left. Removing bed and rescrewing now.

It’s not generally a re-screwing problem. It’s a ‘play in the brackets’ problem and it’s adjustable. When you have the bed off check and see if the brackets are tight in both directions. There should be no excess play. If they aren’t check out this thread:


Ok I removed the build plate and it seemed straight and checked the bracket bolts below. All tight. I screwed the build plate back down with an installation driver drag set to 12. Running a 3x3 test, points 5 and 6 are pinning the calibration card when i move it underneath during calibration. This is using a brand new magnetic build sheet as well. Do I just tighten the screws more in that region?

Checking your earlier post

So yeah 5 and 6 are tight. How do I adjust the bedframe down in that area?
" It’s a ‘play in the brackets’ problem and it’s adjustable. " how to adjust?

It sounds like the probe/Proximity Sensor may not be correctly set. Checkout the instructions at:

not sure what this means, but if it helps snapmaker state that screws used to attach heated bed to platform should be between 1 and 2 nm’s on a torque driver. Mine are all done to 1.2nm - i leveled my bed and plotted the mesh in excel to compare different tightness - at least in my situation it made minimal difference to the mesh and the difference was within what auto bed leveling should accomodate.

I have had two issues:

  1. Y rails not same height causing slope - this is only really detectable doing a slope test, not by visually looking at them. Replacement rails fixed that.

  2. Y rail wobble of ~1.5mm that is really hard to see unless you use a rule or square with measures and to be clear testing the rails by hand before installation to see if there is wobble showed nothing - they don’t feel loose - root cause still TBC. This can be proven by manually jogging the head to a fixed XY coordinate on the bed where you have issues and then lowering the Z until it touches the white calibration like you like, then jog the head on the Y by 10mm forward 3 time and back 3 times and see if the tension on the card in any give place varies.

I have found the 25 square version of this test to be super useful Bed Level Calibration Square Grid by wsreith - Thingiverse just note:

  1. scale the x and y to fill you bed to at least 95%
  2. don’t scale the Y leave it equal to the initial layer height in the slicer (aka do 0.2 object hight and 0.2 initial layer height)
  3. turn of ironing or you will get two layers not one :slight_smile:
  4. after printing use a screen with white as a light box to see where you have issues on the bed
    (oh and use the new firmware’s 5x5 heated calibration)

if you goto all this trouble i would love to see the light box pictures…

I see the issue. The horizontal rails are NOT even at the top. Clearly the right side is lower, thus point 5 and 6 are tight. However I’m not sure how this doesn’t cause ALL points on that side to be tight, rather than just 5 and 6. Regardless I clearly need to disassemble and reassemble to see if I can get them aligned.

They are now equally 8mm from the top of the bar at home. Unfortunately this did not fix the issue, and actually point #4 was tight this time as well.
I’m moving onto the sensor check.