stepper motor sizing

[diycnc]

i am looking to build a 60" x 60" router table. i also want to be able to attach a plasma head on it in place of the router.

its looking like i may be able to get some ball screws that have ~.3" travel per revolution.

the gantry may be near 150lb

i want this to be fairly accurate >.001" and fairly quick.

what size motors should i be looking at?

can i get away with kelinginc

G540 3 axis package (One G540 + Three
KL23H284-35-4B (1/4” Dual shaft with a flat) 387 oz-in + one KL-350-
48 48V/7.3A 115V /230V power supply: $494.95

or should i be looking at bigger motors

3: NEMA 34 640 oz-in Steppper Motors 3 Axis CNC Kit: $709
A:3 PCS KL-5056, 24V-50V, 5.6A Driver
B: 3 PCS NEMA 34-640 oz-in Stepper Motors
C: 1 PCS 48V/ 12.5A, Power Supply
D:1 PCS C10 Breakout board, E-Stop or Limit Switch can be wired

or servos

1: NEMA 34 Servo Motors 3 Axis CNC Kit: $1194

A: 3 PCS Geckodriver G320, 80V/20A

B: 3 PCS KL34-180-90 (NEMA 34) Dual Shaft, 1125 oz-in Peak
90V/40A

C: 3 PCS US Digital:E5-500-250-N-S-E-G-2
Individually Packaged Shaft-Mount Optical Encoder with latching
connector, 500 CPR , fit 1/4" diameter shaft. Molded mounting ears
for 1.812" bolt circle (with Installation Tool) + 3 PCS
CA-FC5-SH-NC-6 Connector Encoder Cables

D: 1 PCS KL-7220, 72V, 20A, Unregulated Power Supply

E: 5V Power Supply

F: 1 PCS Breakout Board for 6 axis, Isolated signal, E-Stop or Limit
Switch can be wired

[diycnc]

the assembly i am looking at has 2 ball screws and 4 linear bearings, the screws are 57" long 5/8 dia and have .2 pitch..

if i want 400ipm i would have to turn the screw at 2000rpm.

would a stepper be able to do that? would a whip be a problem at that speed? on that length and speed?

[ger21]

The G540 package might give you 800-900 useable RPM. As the motors get bigger, they spin slower. If you want faster speeds with steppers, you really need screws with a lead closer to .5

And screw whip would probably be a problem with a 60" screw and 2000 rpm, if you can get it to spin that fast.

[diycnc]

so i would only be able to get 180ipm? that would take .33min to go 60" seems kinda slow

i guess i will pass on the ball screws then