Magnetic bed and 3D print head bumping into model

Hi all!

First, I want to say that I like the Snapmaker very much because of the idea of 3 in 1 and the quality of it’s parts in general, and already made successful things with the laser module and with 3D printing.
I found that the current Luban creates good results as slicer, saw other products like Cura or Orca but they have so many, many possible settings that I did not try them because I simply don’t know which setting to use - there are still enough in Luban!

It’s difficult to find good settings and in case of faster print settings with thicker lines the prints most often fails because they just bend up after laying down the first layer - I think with the faster setting with thicker lines the material is still to hot and when it cools down it bends up and the print fails at the second or third layer.
So the only working setting I found is “Precise and Strong” where each layer is extremely thin and so it simply works. Had a 20cm dice tower which printed over a week and it finished without problems.

Now I tried to print a more problematic print with some overhangs, an eagle lamp model. It printed also since 70 hours without any problem, looking like this (or not… forum shows error uploading a JPG… unfortunately without telling me what’s wrong…).

It was around 7cm high having supports at the inside and also at the outside for later layers.

But then this night, the print head must have bumped against the model with the result that it moved the bed from it’s magnetic ground around 5cm and the model printed now at the wrong place and of course the rest was spit into the air where no support could hold it as there is no. I stopped the printing and I think I cannot repair that, I would need to remove around 2mm very precisely and print all the rest to glue it later… I don’t think that would work.

This is not the first time the print head bumps into the model, I saw that also with the dice tower at the higher ends but fortunately everything finished at the end. I saw it at other model with thicker lines, so I started to move the Z axis before print starts around 0.15mm high to avoid that. It’s often the square think at the corner of the print head (with a cross engraved at it) which seems to be lower than the top of the nozzle so it bumps if the Z setting is 0. Very annoying. Is that a sensor and if, what does it do?

(I would like to show the result, but I don’t know the max values of the forum regarding pictures.)

Is there any workaround to avoid the problem?
I thought maybe to create a better fixture for the bed to avoid that it could be moved away from the base plate - but I’m not sure if that would be a good idea regarding the machine - in the current situation it destroys my model, if I fix the bed, maybe the printhead stick in the model overheating the motor or the filament would start to burn or whatever.
I already read about over extruding but I don’t think that this is a problem here as every layer is extremely thin, so thin that you can’t even see it on the first layer without a strong lamp.
Maybe it would be a simple solution to screw out the nozzle a bit lower than the lowest other parts on the bottom if that is possible.



Hi Christian, this is a problem many of us have encountered in some way. It happens ever once in a while that parts of the print warp and get into the movement path of the printhead, which is not a Snapmaker specific problem, but I had this with my previous printer also. However what is a Snapmaker specific problem is that the print sheet is not held in place good enough by the magnets, and the whole thing including the print is displaced. There are a few solutions for this in the forum - here’s mine: Magnetic print sheet fixation

That said, it will not guarantee that your print will always survive, because with a tighter fixation of the print sheet, it may happen that now the print will break free from the print sheet. However, for me that never happened.

It’s often the square think at the corner of the print head (with a cross engraved at it) which seems to be lower than the top of the nozzle so it bumps if the Z setting is 0. Very annoying. Is that a sensor and if, what does it do?

Yeah, thats the proximity sensor. To adjust the position check this out:

Especially Point 8 “Adjust the installation position of the proximity sensor.”

And check your z hop. I increase it stepwise on high prints.

Thank you both for your tips, I think I’ll try it to fix the bed like this.

And I’ll see if the proximity sensor is higher than the tip of the nozzle, I would say, currently it’s not, but I’ll measure that. Good to know it can be changed.

Better Probe sensor manual here:

Thank you again also for this tip. I’ll perform that after my current print.
BTW: I’ve checked it and the nozzle tip is indeed around a mm lower than the sensor so everything is like it should… theoretically.