Re: Re: Belt vs. Direct Drive

At 02:36 04/01/2003 +0000, you wrote:

>No. You still have the problem of the backlash when you climb mill and it
>never works perfect when you do circles.
>
>Tim
>[Denver, CO]
>Sherline products at Deep Discount
>Mach1 & DeskCNC with Credit Card ordering
>www.KTMarketing.com/Sherline
>www.KTMarketing.com/DeskCNC
>
>----- Original Message -----
> > In this respect I wonder if it is possible to build a very crude machine,
> > with a worst possible screws and backlash everywhere and try to compensate
> > for
> > it in a software to the point of an accurate machine?
> > Alex

Tim -

That is only because the crude approximations to backlash compensation
start with the assumptions that:

(a) a given program will not do both climb milling and "normal" milling, and
(b) the backlash is constant over the travel of a given leadscrew, and
(c) the backlash value is accurately known.

It would be possible to provide sufficient information to the control
software to allow it to do a significantly better job of backlash
compensation than most controls manage currently; however, the real
question is whether it is a worthwhile thing to do, given the alternative
of building a better machine to start with.


Regards,
Tony