Low vs High Inertia for Servo Motors

[AresP]

Hi all,

new member with probably an old question.

In the process of retrofitting a manual knee-mill. Already selected a package from Camsoft and decided the servos and amps from Sureservo.

My question is this :

Sureservo offers both low and medium inertia motors. For my application, being a knee-mill being retrofitted and the goal being precision rather than speed, do you have any suggestions ?

Thanks in advance,

AresP

PS. The machine is destined to primarily work on non-ferrous materials and on low production rates. My gut feeling is for the medium inertia ones but will the low inertia have a real impact ? I am saying all this because the price difference between the two is quite significant, esp when having to buy 4 of them.

[Al_The_Man]

I assume the low inertia ones being higher priced?
The industry recommended sizing of servo's is that the motor to load inertia to be less than 10:1.
This is largely Dependant on the required accel/decel rate.
There are many sizing programs out there that will give you the required size, based on your anticipated parameters.
To use smaller motors, gearing can be used.
Torque is increased by the ratio of the reduction, but inertia ratio is reduced by the square of the reduction.
Al.

[AresP]

The medium inertia ones are higher priced.