I have a measurement problem with my cuts, I have a co2 laser with a working area of 200 x 300 cm. when I cut pieces larger than 100 cm I have an error on the diagonals.
Today I’m cutting 175 x 300 cm panels, I have two different sizes on the diagonals. There is a 1cm difference between the two.
The belts are ok, I calibrated the axles and they are ok, what could be the cause of this error?

I cut 6 panels measuring 175 x 299 cm.
measured at the top, center and base, always 175 cm,
Also on the length 3 measurements and all 299 cm.
the two diagonals instead have a 1 cm difference.
I always have an error on the diagonals, any size cut

Always having an error in the diagonals means that your axes are not perpendicular. You’re making parallelograms instead of rectangles.

The solution is to physically adjust your machine to square the axes. On mine, it would be a matter of loosening the belt on one side of the Y, adjusting the gantry to square it up (hopefully just jumping the belt an integer number of teeth), and tightening it back down.

The fact opposing sides of your parallelograms are equal length means the travel is in sync and proper, but with the machine out of square, you’ll never get rectangles.

A picture being worth a kiloword, here’s a quick illustration. If the green rectangle is what you’re trying to make but your machine is skewed so that you’re making the blue parallelogram instead, the red line will be longer than the magenta line. In order to square the machine, you’d move the right side of the Y axis the direction of the black arrow to bring your blue lines up to the greens.

Thanks CalyJar, I have exactly this problem.
I brought the bridge to the end (zero at zero) and measured a difference of 4 mm between the two ends
How can I correct it?