Calibration pushing deep into buildplate

You can turn off auto-calibration and try doing it manually.

@CasaDelGato
There is no option to do this… when I power on, the only option is to go through with calibration.

you can cheat the auto calibration with either holding the print module to the with your hand or hold the magnetic print surface in your hand and some distance above the heat bed.

I would also recommend checking the proximity sensor before by holding the print surface up to the print module and check the red light on the proximity sensor.

@SchnabsiX Thanks for the input… but, I don’t understand exactly what mean by “with either holding the print module to the with your hand”, but it sounds like you are saying fight the Z-axis stepper motors by grabbing it and using arm strength to prevent it from hitting the bed… then what? it errors out or something and allows me to get to other menu options? This option makes me a bit nervous.

Your other suggestion frightens me, because the magnetic bed didn’t stop it the first time, I don’t see how raising it would change its “mind” on the issue.

I’ve sunk too much $ into this to risk damaging it… I cannot help it if damages itself, but I don’t want to invalidate the warranty because I tried to force the machine into operating in a way it wasn’t designed to operate. I have asked for help from snapmaker on this… if I do something like this, it would need to be under their advisement. Not that I don’t trust you, or that I don’t think you know what you are doing… I just cannot afford to have a $1500 paper weight if something goes wrong. I hope you understand, but I think I’ll wait to see what they say on this. We are on day 3, and I have not heard from them. Hopefully they will respond soon. If not, this weekend, I’ll pull it all apart and try again…

What I meant is, that you shouldn’t fix the print head to the x-axis with the screws, but to hold it there with your hand (ofc just for testing the calibration routine). So you can directly prevent the nozzle from burring into the print surface. (maybe also have the other hand on the off switch for safety)

With rising the print surface by hand gives you the time to switch the machine off before it damages something. Also you can test the proximity sensor without the calibration routine.

Oh! I got you now. Yes, I could see how that would be helpful… Thanks!

btw, I did hear from snapmaker. Apparently there is another thread out there that addresses a similar issue, but didn’t come up when I searched. There are some suggested procedures there. I’ll be tackling this this weekend. Between the suggestions here and in that thread, I feel well equipped to do this.

Thanks gain.

-mg

The other thread: Snapmaker official response to print head gouging?

You can also test/trick the inductive sensor with the metal scraper. The sensor is the little piece that sits at the back right of the print module. Just put the scrapper blade under it and it should sense it as if it is the expected metal in the print bed. That will get you past the initial calibration.

The other thing you likely will need to do is adjust the sensor to be about 1mm up from the print head tip.

These are the steps I used:

1)Have the machine powered off.
2) Attach your print module to the bottom half of the mounting bracket. Basically attach it so that the top screws are mounted where the bottom screws would usually goes. Yes, this means that your print module is hanging very low. Do NOT try to run your machine like this for obvious reasons. The following steps are all done with the power off. This is so that the module is level and steady, and the sensor screw is accessible.
3) Manually position the X & Y axis more towards their centers so that when you lower the Z axis the print head is over the bed. Carefully lower it until the nozzle is just touching the plate.
4) Use something that is 1mm thick (a credit card perhaps), and adjust the sensor down to where it is touching this. The screw is on the back of the module, the bottom left if you are looking at it from behind.
5) Re-attach the print module back in the proper spot.

This should get it to where it won’t be digging into your build surface.

You’ll then need to recalculate your Z-offset that’s set in the firmware to keep from having to adjust it a lot from the touchscreen every time you start a print. I used the quick and dirty that is shown here: https://marlinfw.org/docs/gcode/M851.html

After that I ran my calibration again after heating my bed to 70C.

That didn’t get it wholly perfect. I was still having to raise it by .1mm during the print start to consistently get a good layer, but I currently have it set as an offset in my slicer and it has been working perfectly.

If people need a video of the sensor adjustment I spoke of, I can do that either later tonight or tomorrow. I currently have a print going that will finish at some point tonight. Just depends on if I have enough time before I’d normally go to bed.

I should also note that the other part of my issue was a severely warped build plate. Once I swapped to my spare that was not warped as far as I could tell I had very good layers and adhesion all over.

Well I decided to give the auto leveling another try today so I did an M502 to reset to factory, took my glass bed off and put my the stock steel sheet on. Enabled auto cal and fast cal then did an auto calibration and adjusted the Z at the center point and saved. Verified the settings changed with an M503. Sliced a model in Luban with the fast settings and placed them on the USB factory stick. Transferred the USB to the printer and kicked off the print from the touchscreen. The process started, it performed a quick calibration, heated up and began to print the skirt around my model. I had to adjust live Z by +0.15 during the skirt to get a somewhat decent layer and then disaster struck. The skirt completed and the nozzle dove at least 3mm into the bed as it tried to start on the actual part. It dragged the print sheet back and to the right once it could no longer plow thru the sheet. Luckily I was watching but could not get to the power switch on the back of the PSU quick enough.

Is there a fix for this in firmware yet @Rainie ?
What do I do about my gouged build sheet?

Another odd experience with this issue.
I’ve successfully printed multiple pieces over multiple weeks.
Started on a big complex piece (25 min for Cura to slice, several minute to just download to the SnapMaker, another 5 minutes or so for Snapamaker to parse it)
Started print - and quickly noticed that print was sticking. (different brand of filament) Layers look ok, but didn’t stick.
switched to a small piece to adjust print settings for the new filament.
Switched back to the BIG print.
Auto calibration started pressing into the bed at spot 1.
Power off, power back on, try Full calibration.
Same thing, pushes into bed at spot 1.
Power off, leave it for 30 minutes.
Try again, Full calibration made it to spot 3 or 4 before pushing into the bed.
I’ll try again in the morning.
I’m starting to wonder if there is some kind of over-heating issue with the sensor?

Diving after the print starts sounds more like a Slicer problem.
You could try using Cura to see if that makes a difference.

Mine has never dug in during auto cal. It also has not done the suicide dive when using Prusa Slicer. On this latest attempt I used all factory settings (except filament temp) and sliced in Luban. My issue is my bed is so warped I can’t get a consistent first layer.

What support did tel you about this problem ?

@DroneOn I think this should be a own thread on the forum.
What´s your calibration settings entering M503 in the console?
I´m interested in the offsets of the 9points.

They gave me the same procedure as they have posted. Check that the bed plate is installed correctly and do an M502 blag blah blah. This is after I sent them the logs and gcode file they requested. I will do it again this evening but no matter what I do my bed is not level and there are not enough grid points to properly compensate for it or it is just not working.

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I will have to get that data when I get home this evening. As for another thread, my printer did exactly what the title of this thread says so I think I am posting in the correct location.

Sorry, i thought this because of your picture below, >filament doesn´t stick correctly…

No worries. In fact you can see the gouge in the bed sheet in that photo. This is after I scraped and sanded it down as best as I could. Still not flush so I can’t flip it over or there will be a hump in the bed at that location.

You did verify that the bed support framework is right-side up?
Nuts need to be on the bottom.

Have you checked the level with my “Check Level Hot.gcode” file?

Yep nuts at the bottom since received and assembled.