Stepper driver voltages - using different levels

[Jonathan]

Yep .. with those 3Nm motors the ideal voltage is 70V. Buy the 80V rated drivers and you certainly wont regret it. However, do check that the inductance of the Z-axis motor isn't significantly lower than the other motors as if that's the case it may overheat on 70V, in which case you would have to run it wired in bipolar series, but it'll still be far better than the current system.

Edit: Forgot to mention in the first post - cutting aluminium is no reason to upgrade the motor drivers. If you use single flute tools you'll be cutting at 600mm/min, so no doubt well within what the machine can currently manage. Clearly higher feedrates are required with more flutes, but still much less than that of cutting wood.