Re: [CAD_CAM_EDM_DRO] Re: gearmotors,encoders

Mariss Freimanis wrote:

> Jack,
>
> Good morning! I see no problem mounting the encoder at the farr end.
> It's hard to imagine a leadscrew torsionally twisting even 1 encoder
> count.

Huh? It is most defintely possible. The longer and narrower the leadscrew
is, the worse the problem, of course. But, if you have screws 40" long
and under 1" diameter, the torsional deflection of the leadscrew
can become quite significant with just tens of in-lbs of torque applied.
Take a long, narrow shaft, clamp one end, and see how little torque
it takes to cause observable deflection with a wrench on the other end.
That will be far more than one encoder count!

If this is a high power servo system, it would be a bad idea. For a very
low performance system, with low bandwidth, or if the screws are fairly
short and of large diameter, it will probably work OK.

Jon