Grinding Noise during Calibration

I bought the Snapmaker 2.0 A350. I love it and have been using it for almost a year. I have been printing a lot lately. This morning I turned on the machine and wanted to do calibration. It keeps failing. One thing I notice is when it try to auto level at the 7th point (using a 5x5 grid), it generates a loud grind noise on the Z-axis columns. This never happened before. Also I notice the 1st point is pressing down way more than it should be. It wasn’t like that before. I can visually see the heat bed is being pressed down and wrapped and bounced back. I am really confused and not sure what is wrong since I didn’t change any settings except doing calibration every time it is powered on. It was working before, not sure why suddenly it doesn’t work… Right now, if I print, it seems to have an issue with the first layer.
I upgraded to the latest firmware two weeks ago.

However, I upgraded to the latest firmware on the snapmaker 2.0. It was working fine after upgrade, it has been upgraded around two weeks ago.

Sounds like one of the Z axes has died. You can verify by removing the X axis and jogging Z up and down - does only 1 of the 2 towers move?

Doublecheck all the cabling, and if it’s still a problem contact support. Sounds like you still are under warranty.

All cables are firmly plugged in.

What do you mean by jogging the Z up and down? Do you mean move the mount on the vertical column up and down manually while it is turned off? If so, I can do that no problem… I can move both vertical columns mount up and down also when it is power on using the control interface. They seems to move up and down together without any issue…

I think there is an issue with figure out the bed level when calibration. It seems during the calibration, probing for the surface of the bed seems to be doing way below than it should. I am not sure if I am making sense here… but I never see this before.

Just to state the obvious, the magnetic sheet is on the bed? The grinding noise is only at the end when it’s pressing down? Not all the time when it’s moving?

It could also be that the bed level sensor is failing. When you put a piece of metal below the bed level sensor, do you see a small red light?

You can see a picture here: A350 Proximity sensor not working? - #10 by xchrisd
If the light doesn’t come on there is a problem with the sensor.

Yes… only when pressing against the magnetic sheet/bed… no noise when moving up and down.

Do you see the red light? (second question in my post?)

I don’t see any red light. But the module hub white light comes up when metal is on top of the magnet in the heatbed…when the metal piece move away, the light goes off…

where is the red light anyway? The picture is kind of hard to read… it has motion blurr with it… lol

oh wait… that is the 3d printer head attachment… hold on… let me check again…

Ok. yes the red light comes up when metal piece move close to the sensor…

By the way, @brent113 and @brvdboss thanks for the help. Is there anything else I should check?

Just caught up. Ok I was mistaken, I was thinking the X axis was tilted and causing “grinding” because a module stopped working. That’s obviously not the case.

It sounds like the sensor might not be in adjustment and might be too far from the bed, causing it to not trigger at point 7. You could try loosening the screw on the back and lowering the sensor slightly. Step 6.5 here: