G540 Z AXIS PROBLEM

[MIDDEN300]

i have a gecko g540 on a k2 cnc machine
i am using a vcarve program has lot of z movement all obsolute
the problem i have is the z axis every letter i engrave keeps losing depth
untill it will stop touching part.i recheck my tool offset and it
will be .030-.040 higher than it was set to.i run program 1.0 above part with no
spindle running and get same results.i run z up and down with dial indicator about 50 times
and it repeats every time x y work no problem.
any ideas.

[Galtor]

Tool moving up in holder? Mark the tool or measure the length sticking out. Run the program and measure the length or check your mark.

[MIDDEN300]

i have .500 dia. adapter bottomed out in spindle and i have flat ground on
.125 60 deg carbide engraving tool but to eliminate i will check z to main
z gantry before and after running program,i had also check tool for any
chipping did not see any. thanks for reply.

[Frederic Gagnon]

Also check any slack between the leadscrew and the Z stepper. Maybe you have a loose shaft collar there. Try lifting your spindle by hand and you'll see.

[MIDDEN300]

could not find any problem i changed my progam to just regular engraving
letters and it worked with no problem.
only thing i can figure is gecko control must loose steps with all the
z movment thier is a small z move on almost every line of the program of 4000
lines for 25 letters.using bobcad to program.only good thing it loses depth.

i ran v carve program again after engraving same problem

[ger21]

Cut your Z acceleration in half and then try it.