Autofocus on thin foil material

Hi there!

I recently bought a second-handed MK4 fabkit (Smoothieboard), which I am controlling with lightburn. So far, after some realigning and cleaning, the system is performing according to specs.

One of the challenges I’m currently facing, is cutting of very thin foil, which has a thickness between 100 and 200 µm. I noticed that the auto-focus Z-switch of the machine requires quite a bit of force to activate. I’m afraid that I will force the ball switch through the foil when I perform auto-focusing.

One thing I tried is focusing on a sheet of 1 mm PMMA, offsetting the z-axis by 1 mm (raise bed by 1 mm) and try to cut. However, the machine is always returning to the auto-focus z-height before starting the cut.

Does anyone has some advice or some tips and tricks on how to approach this challenge?

Thank you for your response! :slight_smile:


In Lightburn you can set a Z offset for each layer to adjust for that, which should allow you to do what you want to achieve…


Thanks, I will give it a try!