SM2 calibration

Hi Brodie

I have taken some pictures of the bed and the heat plate.

When I checked for the flatness of the bed, I took the top piece out to check. However, when I placed it back onto the heat plate, it snap onto the heat plate and became flat. I then checked the surface with a ruler again and it is flat this time.

image image image image

Hi magumbasauce

I too, always align the edges properly when putting the plate onto the heat bed.
By the way, your heat bed looks different from mine. Mine has two layers, ie the top layer is thicker than the bottom one.

I guess the A150’s heated bed is very different from the others. I thought maybe there was something in between the flex plate and the heated bed that shouldn’t have been there.
The only other things I can think of are

  • In the front left corner of the flex plate, on the underside, is there any damage or anything else that may cause that corner to site a little higher than the rest of the plate?
  • Have you adjusted the height of the bed leveling sensor at all?

There wasn’t any damage at all. Everything came as they were. The bed looks flat and doesn’t have any area higher than the rest.

I have been following closely to the manual during the assembly of the printer and preparation of the printing. did not adjust anything else. In fact I do not know which one is the bed leveling sensor. Is it together with the 3D printing module?

The sensor is in the 3D printing module itself

Alright, thank you.
I did not meddle with the 3D printing module. Installed it accordingly to the instructions given in the manual.
I really do not know what else and how else to troubleshoot the issue now. :pensive:

First, you can update the software and the firmware via the following links:

Please do as follows to adjust the proximity sensor(for A150 as well):
It seems that you need to adjust the proximity sensor and check the platform.

Normally, when the nozzle is close to the surface of the printing, there will be a red dot in the nozzle.

Please do a calibration process, and record the process to check if the proximity sensor works during the process.

1, Please check if you have assembled the platform in right method. Here is an image for you to refer to.

2, 1, Please adjust the height difference, which one between the nozzle and the proximity sensor, to about 1 mm and then tighten the screws of the probe sensor. Connect the machine with the PC via the provided USB cable.

  1. 1, As for the 1 mm height difference, you can use a piece of credit card as the standard.

  2. 2, Power off the machine and assemble the module in place as shown in the following picture. Loosen the screws of the probe sensor and put a credit card below it. Adjust the height difference and make sure the values of it is about 1 mm, and then tighten the screw.

2, Please be noted that you need to record all the information of the software from the booting to the end of calibration process, which is greatly helpful for us to troubleshoot this issue
3, Please be noted that you need to record all the information of the software from the booting to the end of calibration process, which is greatly helpful for us to troubleshoot this issue. Here is an extension tool for recording
4, Open the software Snapmaker Luban and enter the command “M502“ → “M500“ → “G28“ in order and operate each of them. Change the value of time-out to 15s or 30s so that we can record the settings.
image1234×752 33.9 KB

5, Do the calibrations process by using the touchscreen.
6, Please do not cut off the connection between the machine and the PC during the calibration process.

I have downloaded and updated the firmware of both Luban and Snapmaker (A150).

About lowering the printing module to the lower half, do I leave it that way all the way until calibration is completed? Do I also print with the printing module in that lowered position?

I am not very clear about your point #3. Is the protonface inside the Luban software, the black box that look like the terminal?

Can I connect my pc to the printer via WiFi as both machines are separated in different rooms?

You need to adjust the height difference between the nozzle and the proximity sensor to 1mm, which is proved to be useful. Snapmaker Luban can also be used for the command running.

I don’t know if the leveling bug affects the A150 or not, does the leveling use 4 or 9 points to check?

Ok, I’ve done the steps above. Do I send someone the code of the process or just post it here?

Stupid question… I still don’t see a way to copy the terminal text in Luban. How am I supposed to save the calibration output?

Well I tried a bed level grid after performing the above procedure (update Luban and Firmware, reset to factory defaults and auto calibration) First attempt the nozzle was 4mm above the bed and the “Live Z adjust” was anything but live. It also printed 10mm to the left of center which meant that the left outside border was extruding off of the bed. I turned off auto cal and did a manual cal which got the nozzle a lot closer to the bed but it still prints 10mm to the left of center. Of course with the transposing error in the manual bed calibration I have no hope of easily getting a decent mesh that prints in all areas of the bed.

I was going to run the M900 script but I can’t even get the printer to print a square in the middle now so that is out of the question for this evening sorry.

@Rainie @Edwin any idea when we can expect a fix for the manual calibration?

Found one issue after the M502 and M500, My M206 is now all zeros for X, Y and Z. When I first got the printer the settings were: " M206 X-17.00 Y-8.00 Z0.00 "

Another bug perhaps?

Got the request already, and we will do that option in the coming version of Snapmaker Luban.

If you have problem with the calibration process after this adjustment, please contact

when I put the credit card underneath the print module, what is the distance/position of the nozzle?
The standard is 1.00mm, and the thickness of the credit card is about 0.8mm.

Do I put the credit card under both the nozzle and sensor?
As shown in the picture, you can put the card on the print sheet and lower the proximity sensor to touch it while the nozzle is outside the card.

If I put the card under both the nozzle and sensor, must both the nozzle and sensor be touching the card at the same time?
Just the proximity sensor needs to touch the credit card

If I put the card only under the sensor, must the nozzle be touching the bed, or doesn’t matter?
The nozzle need to touch the heated bed to ensure the right height difference.


Hey, I don’t think I received this metal heating plate (seen in this picture, between bed and magnetic overlay)

Did you buy it separately?

Btw, very nicely designed product, shipped on time, and so far the docs are pretty and good. I have the A350.

And, 2 or 3 successful auto-calibrations (but bad prints), auto-calibrate stopped working, it would always just push down way too far on the back-right corner then go back to center. And yea it started leaving scars on the top layer, my sensor light never turn red.

As of the time of this writing (Dec 2020), I tried:

  • Tried all 3 calibration grids
  • restarted the machine, unplugging the cables (electricity is insane)
  • Switch to experimental mode, factory reset, setup mode: YES
  • install the newest firmware using USB drive (yes FAT32 but hmm, didn’t work)
  • hell, plugged in the USB cable, installed the CH34X driver, nope

None of that fixed the problem.

Eventually, on the device, I just turned OFF auto-set level, I went through all 13 steps of the most complex grid and manually calibrated the extruder Z-height using the calibration card (just enough), and I’m finally printing a nice model :slight_smile:

Hi @aaronsmulktis

There are only two items there, ie the fixed heating bed at the bottom and the removable plate at the top.

By the way, mine is the A150 model, and it came that way.