Cutting too deep

[sawguy]

I have used Vectorart 3D many times and have had to problem, but now I am having a major problem with the finishing tool paths cutting too deep.. I am cutting the wheat sheath #89A from the Symbols and Icons Collection. I run the roughing tool path, and all seems to be just fine. Then I run the finishing tool path and it wants to hog off more than the roughing tool path did. I have tried this 3 times now the first two were write offs. The third time I stopped the machine and re zeroed the z about an 1/8" above the top of the material, and continued on, I am now a third of the way into the project and the machine is now cutting about 3/8" deep all across the workpiece, even though I zeroed the z about an 1/8 above the surface of my material, and it seems to be getting progressively deeper. I figured, that is why we run a rough out pass to hog out larger amounts of material. Has anyone else experienced this? Any suggestions for a fix?

[Hermie]

If you are using stepper motors it sounds like you are loosing steps on your z axis, check for binding or something that is keeping it from running free.

[Adrian]

Check that the Z isn't topping out when it does the home move after the first toolpath.