I know I should post this in the CNC NG but I know I'll get a better answer
here. So far, my only experience with CNC is a Maxnc kit I bought and built
a number of years ago to play with. I make the 3 motors rotate in different
ways and say: "Isn't that cute!" I'm designing a machine that will use
steppers for basis XY movement and it seems the more I research the more in
trouble I'm getting. I have talked to people at Parker and have run their
"Motor Sizer" software and my application should be no problem for an
open-loop stepper system and I think I have the torque issues handled. So,
I have a few basic stupid questions:
Motor Speed: It seems that my 2 axis steppers need to achieve at least 1,500 rpm in order to rotate a ball-screw 5 turns in 1/2 second, allowing for acceleration and deceleration. One guy that makes controller boards says I can't get better than 400 rpm from a stepper. Question: It seems that rated speeds of steppers varies from model to model and often they don't include speed in the specs on their websites...WHY? Is speed dependant on the drive used? Is the drive a limiting factor? Chopper, bi-polar, unipolar, half-step, microstep?
Motor Voltage: I see steppers have a wide range of rated voltages. It seems that a power supply of 5 to 10 times the rated voltage is used. Why voltage from 1.5 to 75 volts? What are the advantages and disadvantages? Can I mix and match different voltage motors with resistors or such?
I know I could just call Parker and get a bunch of stuff delivered for...$5,000!!! and if I knew exactly what I was doing, get $100 worth of stuff on ebay. I guess I'm looking for a more "Middle-of-the-road" approach and would appreciate any step-and-direction (pun) that you may offer. I would love to hire a consultant so as to have someone to blame...or praise. Any takers?
Motor Speed: It seems that my 2 axis steppers need to achieve at least 1,500 rpm in order to rotate a ball-screw 5 turns in 1/2 second, allowing for acceleration and deceleration. One guy that makes controller boards says I can't get better than 400 rpm from a stepper. Question: It seems that rated speeds of steppers varies from model to model and often they don't include speed in the specs on their websites...WHY? Is speed dependant on the drive used? Is the drive a limiting factor? Chopper, bi-polar, unipolar, half-step, microstep?
Motor Voltage: I see steppers have a wide range of rated voltages. It seems that a power supply of 5 to 10 times the rated voltage is used. Why voltage from 1.5 to 75 volts? What are the advantages and disadvantages? Can I mix and match different voltage motors with resistors or such?
I know I could just call Parker and get a bunch of stuff delivered for...$5,000!!! and if I knew exactly what I was doing, get $100 worth of stuff on ebay. I guess I'm looking for a more "Middle-of-the-road" approach and would appreciate any step-and-direction (pun) that you may offer. I would love to hire a consultant so as to have someone to blame...or praise. Any takers?