Quote Originally Posted by AndyUK View Post
I'm not exactly the most experienced here but sounds like a stepper skipping a step to me.

What motors are you using, what drivers, what PSU, and what are the current and microstepping settings on your driver's?

Does it happen when you're doing a specific type of move in particular?
Andy yes it does sound like missed steps but chances of that happening on all axis are very remote unless it's something affecting the pulses which would then affect all Axis.

If it was a new build I'd also say to look at the motor tuning as it's common for people to over tune and use the same settings on all axis. But he's been using the machine for good while now so I doubt it's that either.