The motors are rated at 439 ozin at 3.5 amps. Power supply is 36V & 9.7amps.
The drives are good for 24-50V 1.5-4.5A.
So to get the most overall preformance I would suggest you set the drives for say 2.8 amps. Can't get more than 36 volts out of the power supply but you will need 8.4 amps total from the power supply if all three motors are being used and that is under the max rating.
Set your drives for 0.1126 step angle / 3200 pulses per rev as that would be
micro stepping at 8X and FWIW over 10x is a waste of time and you have no setting for 10x)
There is no motor curve so the max torque based on the above suggestion will be below 439 oz in. Just tune as replied by Dave and see what you can get.
I'll guess axis travel will be around 40 to 60 IPM.
You will be leaving some headroom for cutting forces when you reduce the max velocity found.
It's not how fast you can go but rather the system power, accuracy, and reliability when machining that counts. That said, set feed rates in CAM appropiately for
your "system" and would suggest you experiment some to gain some experience.
Now as far as the motor tuning.......
Haven't the foggiest idea of the specs for those ball screws,if any gear reduction is used, the size of anything you will be moving with your setup.
That's why you need to RTFM. Look at the index and you will see what pages to read. Also you will find in the manual how to have MACH set the
steps/ per unit so you don't need to even calculate. Once you read that you will know how to use the spread sheet in members doc's.
RICH