Hello, I'm a new user/member here, and really do like the forum and instructional videos.  Very well done.   I have a Cinncinnati Arrow 500 that I produce oilfield parts on and set up a new Taig mill with Mach 3 to do the engraving.  So far I am very pleased with the setup, but still have a few items that need attention.

I engrave about 25 (1/8") characters per part, with 4 parts in the fixture.  Material is 1018 cold roll, tool is carbide 60 deg. point, 5000 rpm (fastest available on the Taig), and I use a mist system.  It takes about 5 minutes to engrave the four parts.  Almost every cycle, I have to adjust the Z axis UP from about .003 to .010.  Normally, wear would mean that you adjust down as the tool wears, so I've got something else happening; my tool keeps lowering.  I haven't done any real tuning on the motors, except that I know I'm way slower on velocity and acceleration than I need to be.

Occasionally, my X or Y home will relocated during a cycle with no apparent reason.   The amount has varied from about .1" to about .7".  Not sure what is happening there, either. 
My first question is: if my motors are not tuned to optimal, could that be the reason? 

I've been programming and running cnc equipment for a couple years, but am not an expert; still have lots to learn.  Any hints would be appreciated.
Thanks,
Don B.

Yes, could be you are missing steps, especially on the Z as it needs more from the motors to raise it, if steps are missed on the way up then it will cut deeper on the next pass. Try lowering the acell  a bit to see if that helps.

Hood

Thanks, Hood, I'll give that a try.  Another user suggested I try to separate my cables better and I'll try that also.  I appreciate the help.