Newbie looking at 6040 (China CNC) for polypropylene 15mm sheet

[Neale]

Ignore stepper voltage ratings. As you say, the stepper driver effectively pulses the drive voltage; the driver manages the current rather than voltage but the higher voltage allows higher current pulses which helps develop torque. Confused me at first but the stepper driver will have an adjustable current setting which is more useful. That's also why you use a linear power supply - better current pulse capability.