I do not know what is happening, I cut one job fine ran two dry runs began to cut a pattern and the Z asix started cutting to deep.  .062 was after three passes .625 adn the DRO said -.062   I an hoping with the G540 there is something I have missed.

With it cutting too deep but the DRO saying its at the correct height you have one of two things, first is cutter is being  pulled out of collet or more likely your motor tuning on the Z needs some attention.
 If the motor tuning is slightly too high you may lose steps on a rapid move, more likely on the Z positive direction as you are fighting gravity. So as you rapid up it misses a few steps. Mach has no way of knowing the steps are missed so thinks its at the correct height and then commands the next move down and it will actually go further into your material.

Drop your accel by 20% and see if that helps.
Hood

With steppers, you need to provide lots of margin when setting velocity and accleration.  I'd test them to the limits, then back off at least 30%, if not 50% on accel and velocity.

Regards,
Ray L.

This has to be chalked up to operator ERROR.  God, when I setup last night forgot to tighten TWO screwes on the lead screw.  That allowed the Z to loose setps.  Now that is stupid but that is the fact of it.

I am cutting now no problem so far and the z is behaving since I have everything tight now.  Thanks for all the help.  I have got to start thinking here. 

"I have got to start thinking here." - But that takes all the fun out of it!  :-)

Regards,
Ray L.

*l* yes, but I should know better.  I really feel stupic now.  Of all things to think of last should have been the first thing I thought of. 

The best part of this one is at LEAST I KNOW WHAT CAUSED IT!  That G650 really runs nice.  That machine has never ran this good. 

Happy to say so finished 4 complete jobs about an hour and a half each without a hitch.  What a difference it makes when things are working correctly. Even the operator made no mistakes on this run.  Now if I can only make that a habbit.

Being new to this makes it a bit harder as there is so much to watch.  First Vcarve and it can really mess you up if you do not have setting correct then mach3 and it's controller.  And finally lasty but not least the operator. I think we are moving now.

Thank you all for your help