[jchancel]

I have a 700x500 ebay laser / ruida controller running rdworks which is new but I can't solve an issue with the X-axis losing steps.

I can cut a 100mm square block on the left side of the machine which measures with a digital caliber perfectly, but the same 100mm square on the right side of the bed will measure 99.5mm on x-axis. Y Axis is perfect in all corners. The machine is consistent. I can do the same cut over and over and it repeats exactly the same. Makes me assume the stepper isn't skipping.

Things I have checked / verified:
1) Mirrors aligned well and step length calibrate in top / left corner - machine is cutting material very well
2) Machine is square - verified by cutting large square and checking with large square
3) Rails are tight and very smooth - verified by removing belt and sliding head
4) Problem is isolated to the X axis. Y axis cuts perfectly 100mm on all corners.
5) I have replaced the X axis stepper, pulley, and driver with a 2 phase 1.2degree motor - no improvement
6) I have replaced the X axis belt - and tried loosening and tightening
7) I have slowed the machine way down.

See Attached: The step loss is linear across the bed it appears. To eliminate Y axis completely and demonstrate problem, I have create dots across the x-axis every 10mm. As you can see in attached, on left side of bed 10 dots = 100.03mm. But as you move across X-axis, 10 dots becomes 99.58mm in the center of the bed and 99.34 on right side of bed.

I'm at a loss. Anything else I should check.

[Batman53]

That's a pretty tiny difference on a "not high end machine". It could simply be due to the geometry of the rail at that point. Check it for "perfect" straightness.