[Styler93gsx]

I have a 140lb table 622 Newtons and have played with some online calculators and can't seem to get a definitive answer on torque and of what I should expect.

Right now I have a 2.5hp 4000 rpm Brushless servo driving a THK C5 ball screw 2520

Ball screw diameter is 25mm
Lead is 20mm
spec sheet says .05 efficiency (I think I'm reading that right)online calculators say use 90% for rough estimate

I'm trying to figure out is if I should have gone with a 2505 ball screw instead
Ball screw diamter of 25
Lead 5mm

This is load is a 30"x30" x.5 in Steel plate for the bed of my CNC machine.

What kind of rapids can I expect out of this machine?
What kind of torque can I expect of of this machine?
What kind of accelerations can I expect out of this machine?


Thanks in advance.

[ger21]

At 4000 rpm, your machine would rapid at 80m/min. However, it will never have time to get moving that fast.

Your motor should have a rated torque specification. Your acceleration will depend on the motors torque.

[UA_Iron]

with a 20mm lead and your peak torque probably in in the 3000RPM range - I would consider gearing down.

[Styler93gsx]

Attachment 298558

Here is the spec on the motor sheet but I don't understand what it means by the torque. Is it saying that it is 4.8 inchlbs per amp.

On the side of the motor it says 36 amps RMS peak at stall and 12 continuous amps at stall does this mean that I take 4.8 inchs and multiply by 36 amps which comes out to be 172.8 inch lbs which equates to 14.4 lbs of torque and on the spec sheet down at the bottom theres a (3) beside the peak valuve sqaure wave and the notations says torque per phase. So there is three phases does this now mean 43.2 foot lbs of torque

How does this torque effect my ball screw lead torque.

[steve123]

Please give the length of your ball screw. The ball screw inertia can be more than your "load" depending on diameter and length.

[Styler93gsx]

My ball screw is 710mm

[Styler93gsx]

So I have a ball screw 710mm 25mm diameter and 20mm lead this would equate to 3150 inch per minute or 52 inches per second. This is way out of my range of speed. I understand this. Well in a perfect world where the load is nothing. But I do have a load and I don't want to go 52 inches in a second. I'm wanting to go more along the lines of 15 inches a second which would equate to about a 1-4 gear reduction. If I did choose a 4-1 gear reduction would my servo still be strong enough to accelerate a 200lbish load (adding and subtracting vices) in an awesome manner, (within an inch or two) or do I need to increase my gear reduction from 4-1 to 10-1. This would decrease my overall inches per second to 5.2 inches a second.