deviations along axis

Hello!
I use linuxcnc 2.6.3 . I recently replaced the microstep drivers and configured in stepcofig wizard to be accurate to 0.001 mm and everything works properly in manual mode, but when I put a complex program with loops , etc. x and y axis do not do any deviations along the axis or y-axis in each cycle moves(Z) deeper, y axis of 4 mm in my case + . please help

Sounds like you are saying the X and Y axes are fine but the Z axis is not were it is supposed to be - worse as the program runs.

The usual suspects:

1 mechanical slipping - like couplings or set screws

2 velocity/acceleration settings too high - losing steps because the motor can not move as fast as it's asked. Z is often the worst because of gravity.

3 electrical noise on step signal lines - the drive is getting false step/direction signals from stray induced electrical pulses

Try using shielded cables that are grounded properly (one end only) and routed away from each other and from other strong noise sources.

Hope that helps

Chris M

In addition to Chris' s response also double check that the error is not in the programing.

After running the problem program if you return Z to a know location is it correct or has it deviated? All offsets correct ?

Rick G

as well as Chris has said , beware of running microstepping drives at a high step rate , one trade off is as you try to increase velocitu and speed , you loose torq
especialy on a z axis where your also fighting gravity , so slow things down a bit say 50% and you'll find it will probably correct . then go from there .

you'll always find the z will loose or slide down , due to missing steps