Hmm....
0.01mm ( 0.0004") depth of cuts which requires a vey accurate SYSTEM which includes tuning and setup.
What kind of machine are you using?
Post your xml file.
If it were a "motor power" as someone suggested, it takes more power to dig deeper into my PCB material. Maybe it's when I lift the Z axis?
As Terry replied it could be the motor. For very small moves the motor needs to be capable of delivering high acceleration and thus at 0.01mm
move it's almost instanteous.Thus you can loose steps which could be random or consistant.
You need to meticulously tune the steppers and then find your max
vel and accel that delivers repeatable results. Very seldom will the machine be able to move at it's resolution. Practicaly speaking "zero"
backlash is not to be had.
It gets very difficult to find those very small things that affect accuracy since many things can be the cause of it.
You should be able to say, with out doubt / absolutely, that it is not a speed problem.
First tune the steppers, do tests, to verify movements, etc. to know exactly what each component of the system is contributing or limited to.
BTW,
Resolution is 1/steps per unit...so for say 23000 steps per inch
resolution is 0.000043".
RICH