Re: Encoders: on servo or on guideway?

Thanks, that makes now that I think of it. I can't wait to have my
machine up and running, I will be posting pics soon.

--- In CAD_CAM_EDM_DRO@yahoogroups.com, "Tim McCoy" <lotus_14us@y...>
wrote:

> Hi Peter,
>
> If you look at the machine you are using, you should be able to see
> the difference. The drive system, no matter how precise has a

number

> of "interfacing" points; couplings, drive screws, and slides. Each
> one of these can add an error, no matter how small. If you use a
> linear encoder on the machine axis you will be after all the
> accumulative errors in the system; assuming the spindle or tool
> holder do not have any slop. What you are doing is increasing the
> precision
>
> Obviously if you can afford it, you want the most precise machine
> available, and on some machines you will find both rotary encoders

on

> the servo motors, and linear encoders on the machine axis.
>
> Another way you could look at the problem is manual machining using
> the dials to position a part or cutter, as opposed to using a

digital

> readout (or direct measurement). If you have a brand new Hardinge
> toolroom lathe you can be pretty sure the dials will be more

precise,

> but if you have an old worn Atlas, you might not want to trust

them.

> If both have a set of good linear encoders, and you read off of
> them, the chance is you will have a more accurate part. With my old
> worn Atlas (no readouts), I will use more hand measurement, and can
> still make a part as accurate as the Hardinge, but it will take me
> longer.
>
>
> In CAD_CAM_EDM_DRO@yahoogroups.com, "peterboutakis" <peter@b...>
> wrote:
> > Which is better? An encoder that is incorporated into the linear
> > guideway or one that is part of the servo motor?
> >
> > There is a company called Hiwin that sells an "intelligent"

linear

> > guideway system which has the encoders built into the guideway
> rail.
> > Is this better?
> >
> > Thanks, Peter.