Camera calibration doesn't work on thicker objects?

Trying to make sense of camera calibration.
I’m trying to use it on a piece of stock that’s 23mm thick and can’t get it to line up at all.
I did some tests and printed out a grid to see what was happening:

I did the camera capture on the paper flat to to the bed and then using that I arranged a smaller grid and laid out some letters to use to check:

Those results are acceptable (although vertical is off a couple mm but I can adjust for that):

Then I tried a camera capture of the grid 24mm off the bed. The grid starts to show some problems (center squares aligned, but outer squares are off, had to change size/shape of letters )with alignment :


Ran a pass and it’s completely off:

Am I missing some adjustment or way to compensate or calibrate for a thicker piece? Something wrong with my camera? I assume that if I tried to do the calibration on top of a raised piece that the toolhead would slam into the piece.

Any suggestions?
-Steve

Hi @sdj544

  • Please send me an image which shows me the gcode file in the workplace.

  • Check the paper for flatness and is the paper creased?

Looking forward to your reply.
Best regards

Paper is completely flat and not creased

You can see that the vertical lines of the paper are not aligned, but these lines are aligned above the photo. Is it possible that the paper was moved during the cutting process.

No the main paper wasn’t moved at all. It’s taped down.
The part that got cut out moved slightly from my fan but it still didn’t cut in the right place.
None of the letters ended up anywhere near where they show in the preview
-S