I am in the process of designing my CNC wood router. I did my calculations and am comfortable with 380 oz-in steppers, which should give me a factor of safety of ~7. I've found many potential steppers on ebay, but I'm unsure of what other parameters that I need to look at before (1) choosing a final stepper and (2) choosing an appropriate set of drivers.
Here is what I know:
1. Lower inductance is better <2.0 mH - but there doesn't seem to be many around with an inductance this low
2. the motor needs to have sufficient torque at my design RPM. I can read the motor performance charts, but I'm not sure what to do with the "1/2 step" (or other fraction) at the top of the chart - should I derate the torque chart based on this?
Here is what I don't know:
1. What do I look for in a driver ( should it be at least the max current of the motor? do I need to look at any other factors?, how to choose between unipolar, bipolar, etc? Is one better than others for CNC applications?)
2. How to choose a power supply?
3. I'd like to buy a set of 3 steppers, drivers, and a power supply for ~$200... does this seem reasonable?
thanks for the help!
pete in upstate NY