SM2 calibration

Hi guys. I am new to 3D printing and have gotten SM2 as my first 3D printer.

I have done many calibration, following closely to the instructions given from both the manual and video. Prior to each print, the nozzle will always move itself to the left bottom of the plate dig itself into it while waiting for the plate to heat up, thus melting and creating a small hole at the corner of the plate.

When it is ready to print, the nozzle will drag along the plate, causing a mark on the plate from the corner to the center.

May I know if this is normal, as I do not know how the nozzle suppose to do. I watched other 3D printing videos but never notice the same behavior from the nozzle.

Thanks guys in advance.

At first I would check if you mounted the metal grid that supports the heated bed is mounted the right way (or upside down).
Then I’d check if the proximity sensor mounted too high up and if your print surface is warped.

No. The print head should be at the print height which is somewhere around .2mm or .3mm so something is amiss.

Hi, thank you for your response.

I checked everything and all was mounted correctly and properly. Anyway, I unassembled and reassembled the printer, making double sure everything was assembled and tighten properly again.

Prior to the above-mentioned, I did five level testS.

The results:

Print #1) everything was in a mess. Noticed that the filament is quite flatten. Some difficulty in removing the print out from the bed.

Print #2) recalibrate manually. Very slightly better print. However the filament was not properly adhered at points 4, 6, 7, 8. Very difficult and almost impossible to remove the filament at and around point 9. It was as if the filament has gone into the bed.

Print #3) recalibrate in auto mode. Set Z-offset up by 0.05mm. Print was slightly better and easier to remove from the bed this time. However the filament was not adhered to the bed at point 6 and 8.

Print #4) recalibrate in auto mode, with the slightest resistance when adjusting the Z-offset. This print is the best albeit the filament did not adhere properly at point 8. There were some gaps of the first layer at point 8, tiny gaps near points 1 and 2. Otherwise it is almost perfect.

Print #5) I tried to do a manual recalibration again. I notice every time during manual calibration, when come to the right side of the bed, especially bottom right at point 3, the nozzle will press against the bed hard after pressing 0.5mm down five times. However at the left side of the bed, ie around points 1, 2, 8, the nozzle will only press hard against the bed after pressing 0.5mm down seven times. I immediately paused and stopped the print when the nozzle reached points 9, 4, 3, as the filament was pressed into the bed again.

Overall, I noticed that the nozzle tends to be closer at the bottom right side of the bed, while slightly further from the bed at the bottom left.

The print head always position itself there since day one on my first print. It will only position itself merely touching the bed only if I calibrate in such a way that there is almost no resistance during the z-offset adjustment.

Attached is the result of the prints. There are always some issue at bottom left quadrant whereby the nozzle will be sightless further from the bed at some area. Print #6 was done after reassembling of the printer and auto calibration.

And yes, the nozzle still moves and start “inside” the bed at bottom left prior to the printing for all prints.

I’d check the print surface for warping (with a ruler or this Software)

Also is this a metal plate between your heated bed and your print surface?

Alright, after checking the plate with a ruler, the surface is warped and uneven. I have not done anything with the plate and it has been left on the heating bed since day one. Is there anyway I can resolve the uneven surface?

The metal is part of the heating bed.

The mesh bed leveling should account for a warped bed.
It looks like on your photos you have the Heated bed circuit board that the removable sheet is not directly on the heated bed? I can’t tell specifically what I’m seeing, but if it is what it looks like I think I know exactly what your problem is. Would you be able to take a photo of the edge of your of the build plate and then take the flexible sheet off and photograph what is underneath?
As I said, I could be completely misinterpreting what I am seeing.

right, per what i expect Brodie is thinking and others have asked, i’m not totally sure what i’m looking at in your pic or why your stuff looks super thick. For reference because I’ve gone through several spools of nearly perfect prints (took a bit to get the relativity of the calibration to where the auto-calibrate would land relative to the first layer, but i got it), here are pics of the side and top corner of my plate for reference…

with the build plate attacked, it should feel VERY strong and secure to the heated bed. and whenever i take it off and put it back on, i take care to make sure the corners/edges are lined up with the edges of the plate. (and 0,0 = 0,0, not totally sure that matters but I think it did say that in the setup).

so from your picture… you have this huge plate in there for some reason. where did that come from? my heated bed (which you can see the screw there) is screwed into the open lattice piece, which is screwed onto the Y-rails, and that’s pretty much it.

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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 https://chrome.google.com/webstore/detail/loom-video-recorder-scree/liecbddmkiiihnedobmlmillhodjkdmb
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.
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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.