Re: [CAD_CAM_EDM_DRO] Re: what the world needs now ... backlash aware stepper motor drive r

"Daniel J. Statman" wrote:

> Are you suggesting that the "add reverse steps to take up backlash" should
> not be used in the interim, before more advanced control software can be
> written?

Not at all, Just pointing out that just because a particular program "says" it
has backlash compensation does not necessarilly mean it will "fix all- cure all"
backlash problems.

> Do you think that it makes the machine work less well compared
> with no backlash compensation at all?

It can.... I think the original poster, Sean, indicated it caused him additional
marks in his material.
I personally have only built machines with either Ballscrews or Leadscrews, all
with preloaded antibacklash nut techniques so I have not been forced to use the
adjustments. I have seen more than one comment in NG's that pointed out that
their "backlash" settings didn't seem to take care of *all* backlash needs
depending on what toolpath they were running. As toolpaths get more
sophisticated, especially 3d work, Backlash comp can fall behind because often
the control program does not have the ability to calculate all of the
"possibilities" with some of the angular/helicular moves.

Backlash on a Lathe is a little different yet. The lathe "bit load" is really
comes from a whole lot less different directions, than a rotary tool in a mill
application. Here backlash settings can work much better.

> Obviously, I am assuming that we are
> trying to control a machine that has backlash for whatever reason. Not
> trying to incite anything, just honestly asking questions that I do not know
> the answer to.

Your right... Whatever reason... I try to build without backlash ! It's
obviously not always possible, especially on a older machine retrofit, and
especially on a hobby budget ! I just simply am stating that even though economy
Controls have the function "listed" in the sales literature, does not mean it is
the cure all. There are way too many factors that can come up on a multi axis
machine, to make super accurate backlash compensation a real easy programming
project.

I'd be interested in hearing from some other economical controller programmers
what their view is. I am not a programmer. I just had the issues explained to me
and subsequently saw them in my head. I could see the challenges.

Chris L