Re: Lost steps

Update:
After quite a few hours of fiddling without much progress, except to
improve some wire connections, I decided to romove a motor and watch
it. I was amazed to see it not only stutter once in a while but
sometimes take a backward step.

Up until now I have wrapped the signal wires inside the cabinet with
aluminum foil and connected the foil to ground, reduced the
acceleration in EMC, reduced the feed speed, and retested the boards
as the Camtronics direction instruct. I also moved the parallel port
cable away from all other wires.

Is it possible my motors are bad? I don't know their history.
Might I have them wired wrong? They seem to make 99% of their steps
right.

What else might help someone figure it out?
The stutters are not at any particular part of the move. They vary
fro
one every third revolution to several a revolution. During an hour's
no load testing the motor gets quite warm, maybe 100 degrees.

Anyone???

Jerry

--- In CAD_CAM_EDM_DRO@egroups.com, Joe Vicars <jvicars@c...> wrote:
> True but the cost of precision is comming down. Precision has
two components, accuracy and repeatability. Machines in general
> are becomming more repeatable (if not more accurate) and these
machines are used to build other machines thus improving the overall
> precision of what is available. The bell curve is getting
narrower.
Six sigma and all that.
> Peace
>
> Terry Ackland wrote:
>
> > ---Ron,
> > I have mill drill in my basement and the lead screw is all over
the
> > place. If I need to do anything fussy I have to set up an
indicator
> > because I cannot trust the dials.
> > I can remember many years back working on a new Bridgeport with
> > digital readout and expecting it to perform like a jig borer. The
> > first job sorted that notion out!
> > You have to pay for precision and you cannot really expect it from
> > what most of us hobbyist are prepared to shell out for.
> > Terry
> >
> > In CAD_CAM_EDM_DRO@egroups.com, Ron Ginger <ginger@s...> wrote:
> > > Ozzie@h... wrote:
> > > >
> > > > In repeated attempts to determine the backlash on the axis, I
> > find
> > no
> > > > consistency in dial indicater readings. On the X axis I lose
> > > > .002-.003" cumalatively in one direction. On the Y axis the
> > readings
> > > > are erratic with variations in the.002" area.
> > >
> > > Everyone else seems to be looking for electrical causes, Id
look
for
> > > plain old mechanical ones. And this is exactly why I do not
think
> > > software compensation for backlash is worth it. You are finding
its
> > > almost impossible to accurately measure the amount, so how can
the
> > > software accurately compensate?
> > >
> > > Variations can come from wear in the screws, variation in
friction
> > from
> > > move to move- chips in the way, etc. Try making the moves under
as
> > > constant a load as possible- like while cutting a slot in some
> > stock.
> > >
> > > The only solution to backlash is elimination! Ballscrews or
Moglice.
> > >
> > > ron
> >
> >
> >
> > Welcome to CAD_CAM_EDM_DRO@e...,an unmoderated list for the
discussion of shop built systems, for CAD, CAM, EDM, and DRO.
> >
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