Re: [CAD_CAM_EDM_DRO] Reduction

jbordens wrote:

> The gears and pulleys thread has got me thinking about how I'm going
> to design my setup once all my parts arrive.
>
> Originally, I was going to use belts and pullies to handle the job,
> at some sort of reduction.
>
> I'm using the Camtronics 600-in-oz peak servo motors (torque constant
> 50in-oz/amp). My calcualtions show that un-reduced, the motors will
> generate 45ipm at 300in-oz and generate 1176.5 lbs of force at the
> tool. (assuming no lead screw friction)
>
> 45IPM is too fast, of course. I'll probably be dealing mostly with
> aluminum, plastic, and in some rare instances, steel.

45 IPM is to FAST? Really? How about rapid travers, where you are going
from one place to another? On a Sherline, 45 IPM might be fine, but on a
larger machine, that may be an annoyance. Why will you only get 45 IPM?
With a 5 TPI screw, that is only 225 RPM!

> By gearing 2:1 with pullies, I add backlash, increase resolution and
> force, and reduce speed. Seems like a good idea except for the
> backlash.

Toothed belts do NOT add backlash, if the belts are tightened properly.
When the belts are severely worn, there may be backlash, but then you should
replace the belts.

>
> My question is this: which is my best option:
> 1. unreduced and direct drive. I guess in this case I'm relying on
> the software to control the feed rate?

The software ALWAYS controls the feedrate, otherwise the system would
run out of control.

Jon