What's better Ford or Chevy? That is an emotional or personal opinion type of debate and is therefor unresolvable. The debate betwen steppers vs servos will also be unresolvable so long as it is argued by fanboys instead of facts.
I have lost count of how many of these debates I have read and probably less than 10% of them have any facts whatsoever.
Servos are more expensive than steppers in the same way as a Corvette is more expensive that Ford Escort. It is frankly rediculous to compare those two cars based on price alone and make a blanket statement the they are both 'cars' and therefore the Escort is 'just as good'
If your objective is to take your kid to school over surface streets at 35mph max, THEN there may be a valid argument there. If your objective is to autocross without building a race car from the ground up, then it matters zero how little the Escort costs because it is simply incapable of doing the job.
If one prices out, using CURRENT pricing, servo motors and the required encoder and driver and a stepper and required driver in cases where anything resembling equivalent performce is a criteria, then steppers and DC servos are very comperable in price.
Exactly how does one go about comparing steppers and servos? I have seen people compare the torque, but that is a completely invalid comparison because the motors are rated differently and have vastly different charactaristics. Torque is a STATIC measure. That's not an opinion, that is a fact. Moving objects requires POWER. That is also a fact. POWER is about doing work over TIME, also fact. Torque is ONE number in the equation. I did a comparison of stepper vs servo of similar 'rated' torque and posted it in this forum. I also posted the formulas used so anyone was free to discredit them. Nobody did. The servo was many, many times more powerfull.
A Corvette motor has 500hp and a semi diesel has only 300, therefor a Corvette engine will perform better in a semi truck than a diesel. That is simply an uneducated statement and is the type of logic that often defends stepper motors.
I have to agree with whoever said that the stepper powered full size mill that was used as an example is pitifully slow. I would add that is is also pitifully weak.
Servo motors top out early in the power game and above that there is only a choice between DC servos and AC servos. A Ford Escort gets much better mileage than a semi, so putting a Ford escort engine into the semi would result in much better mileage for the semi. This is also the type of logic that defends steppers on big machines.
It is really like comparing a pickup truck and an earth mover and saying the pickup is 'just as good' because it also can move dirt from point A to point B and it is cheaper.
Flame suit *on*
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