CNC Servo motor gear ratio: overheating. EMC step rate. Table speed

Hi people.

We are retrofitting a small mill. The force required to move the table
is low, ie 25 pounds moves it with the screw removed.

We are using EMC as the controller. I've read it has a maximum step
generation rate of 5 KHz.

We've purchased 620 oz in servo motors from Dan Mauch (Camtronics) with
500 step per rev encoders.

We are planning to direct drive a 4 or 5 TPI ball screw.

My calculations show that 600 oz direct driving a 5 TPI ball screw will
generate a force of 1059 lbs.

The reason for wanting to direct drive the screw is speed. EMC
supposedly has a maximum step generation frequency of 5 KHz. 5 KHz/ 500
steps per rev = 10 revs per second or 600 RPM. 600 RPM x 0.2 = 120
inches per minute, which is slower than we want. We were thinking of
using 4 TPI ball screw to get the speed up to 150 IPM.

Question: will the motors suffer from heating problems ? At a feed rate
of 5 inches per minute, the motors will be turning 25 RPM.

--
Kim Lux <lux@...>