4 other people and I are making a CNC milling machine for my senior design class and I was put in charge of the electronics. Initially we were going to use a stepper set up but the sponsoring professor seems to prefer servo motors. From what I've read on the forums I will need the following components for a servo system: interface board, drivers (1 per axis), amplifiers (1 per driver), servo motors, encoders, coupling for motors to screws, and a power supply. Since I am new at this I have a few questions.
1) I read somewhere that a 1:1 gear ratio is adequate when connecting steppers to screws. Does this apply to servos as well or is gearing reduction necessary?
2) How much torque is enough torque for the servo motors? We plan on building our machine out of steel, with 18" X 12" X 6" travel, so I supposed it will be a relatively big machine. Would a servo like this be enough?
3) With a budget around $1500.00, including building the machine, would a servo system be feasible or should I go with steppers?
4) Would the power supply for a brushed DC servo be different than one for a brushless AC? If so what do I look for in a power supply?
That is all I can think of for now, but I am sure I will have a lot more questions as this project goes on. Any replies would be greatly appreciated.