[DumbandMoody]

I've upgraded a cnc from more or less the frame up. I have 3 nema-34 stepper motors (2.2v 5.5amps), 3 two step DM556 microstep drivers, and a Mach3 USB CNC Interface running on Mach 3. Everything seems to be correct when I use the Mach 3 axis calibration and it doesn't skip, but when I cut a board, it becomes uncalibrated and several of the cuts are off. For ex: elongated circles as the cut goes along, boxes the are longer than programmed, and retuning to home several inches off. I've also noticed the motors will skip when I manually input a direction but release before it reaches a certain speed. I have tried to tune the motors and increase the steps in the microstep drivers but have not had luck. I am new to cncs and am sorry if I did not elaborate enough.

[dazp1976]

If you'd done your research properly you would have seen that nema34 always come with bigger dm860 drives and at least 60vdc.

They don't match well with smaller 556 drivers and a lower voltage.

Guarantee your issue is to do with lacking voltage. When you speed up it will slip guaranteed. I've had to go up to 80v on my system as 60v was still lacking and swap to DM860T drives.

You have 2 options.
1. Switch to nema24 size motors of 3.5 to 4nm with 48v supply. or...
2. Swap to dm860 drivers and 60v supply.

That's as blunt as it gets.