Z Offset Limit?

[Garry Bartsch]

I changed build surfaces from a 3mm piece of glass with 0.4mm PEI (total thickness 3.4mm) to a 3mm piece of glass with hairspray on it (total thickness about 3mm).

Since my z height in Marlin was perfect I thought I would just use Kisslicer's Z Offset to compensate for the new build surface. So I entered -0.4 in the Z Offset but my first layer wasn't right. It was too high.

I kept increasing the negative Z Offset till it read -0.7 but the first layer wasn't right. It was too high still.

So I set the Z Offset back to zero and went into Marlin and increased the machine z height by 0.4mm and the first layer was perfect.

Does anyone know why this happened? Is there a limit to how much Z Offset will actually change the z height?

Thanks

[pjr]

It would really help to see the G-code for the slice with the offset.

Peter

[Garry Bartsch]

Thank you for replying. But I'm sorry, I've made too many prints after to know which file contained the error. I likely over-wrote the file.