Re: need help emc backlash

ray
i am running steppermod its setup for 5000 steps per inch or 500
steps per revolution and yes they are standard acme
i will have a look at the posts on nuts
thanks
peter

--- In CAD_CAM_EDM_DRO@y..., Ray Henry <rehenry@u...> wrote:
>
> Peter
>
> Freqmod or steppermod? How many pulses per unit? Unit?
>
> 0.027's a lot to expect. Sounds like stock acme. You might read
up on some
> of the posts where people have done things like casting new nuts,
using two
> and a spring between, or splitting a nut and pinching the halves to
get less
> backlash.
>
> EMC can do it but you will not get good contouring around the arcs
where an
> axis changes direction. Cutting forces will drive the axis ahead
of
> compensation.
>
> EMC feeds backlash pulses in over a number of motion loops rather
than all at
> once but it is rather easy to run into following error problems if
you have
> not made provision in your ini to feed those extra pulses into the
normal
> axis pulse train.
>
> I'd set MAX_VELOCITY in [TRAJ] a bit higher than it is set in any
one [AXIS].
> Then I'd start commanding circles at fairly low feedrates and watch
the
> motion when each axis changes direction. Make bigger differences
between
> these variables if you still get following error.
>
> HTH
>
> Ray
>
>
> On Monday 01 July 2002 03:05, you wrote:
> > Message: 24
> >    Date: Mon, 01 Jul 2002 05:59:46 -0000
> >    From: "armadhas" <peterh@h...>
> > Subject: Re: need help emc backlash
> >
> > jon
> > the ammount of backlash is .027 new machine still setting it up
> > peter
> >
> > --- In CAD_CAM_EDM_DRO@y..., Jon Elson <elson@p...> wrote:
> > > armadhas wrote:
> > > 
> > > > hi
> > > >
> > > > i am having trouble with emc
> > > > when the backlash amount is set in the axis setup
> > > > the machine runs at the set feed rates but the backlash when
> >
> > tacking
> >
> > > > it up runs at full speed and it seems to make no differnce
> > > > what any of the speed setting are set to in the emc.ini file
> > > > it takes it out that fast it skips steps on the steppers
> > > 
> > > How much is your backlash?  I think the scheme used is really
> > > only designed for backlash in the .001" range.
> > > 
> > > Jon