Quote Originally Posted by Jonathan View Post

That doesn't look very random! In fact that's an excellent linear correlation (R2=0.9996) so it looks like an alignment problem to me. If you hadn't said that the bed was surfaced I would say that it is the gantry that's not level and if you hadn't said that the cut with a V-cutter looked fine I'd say it was the bed/PCB that's not level as a straight line like that implies one or the other is inclined.
Yes Machine setup was my first thought Jonathan but the leveling of the bed rules this out.! Not sure the pcb would be so consistant increasing thickness.?

Thats why I turned to pulse timing issue.? This would be repeatable to this level.!

I feel for hank because things like this can drive you crazy.!!