Re: [CAD_CAM_EDM_DRO] Re: Counterweighting the Z axis ?; Power off position holding ?

All the CNC conversions we are doing are ballscrews/servos, all three
axes on this mill included.

I though that backlash could be a problem under the weight of the head
AND one can use significantly smaller servo motors with ballscrews, ie
1/3 the size.

I think we'll be counterweighting.

Kim

On Tue, 2003-07-08 at 10:09, deanc500 wrote:
> Hi Kim, I am in the middle of retrofitting a ZAY7045L square column
> mill/drill. Are you converting the Z to ball screw for better
> accuracy, reduced friction, or to get rid of backlash? I would say the
> best thing to do if you want to go to a ball screw is use an electric
> brake on the motor. The simplest solution is of course to use the
> original acme lead screw. There is no way that will move when power is
> removed. Do you think backlash will be a problem even under the weight
> of the head?
> Dean
>
>
>
> --- In CAD_CAM_EDM_DRO@yahoogroups.com, Kim Lux <lux@d...> wrote:
> > Glad to hear I am not the only one.
> >
> > The problem with springs is that their force varies with where the head
> > is. Maybe they could be adjusted for zero force in the home position.
> > That wouldn't help for an EStop though.
> >
> > A regulated air cylinder could give a constant force with any position,
> > but I'm worried the air dynamics would mess up the head motion.
> >
> > So far the best solution seems to be to counter weight it and/or apply a
> > bit of drag to the ballscrew drive.
> >
> > Kim
> >
> > On Tue, 2003-07-08 at 08:46, tsalaff wrote:
> > > Kim,
> > >
> > > I'm dealing with the same problem right now although my Z axis is only
> > > 40 lb.. Going to try making brackets to anchor support springs. Will
> > > report on how these work.
> > >
> > > > motor the milling head will slide down the column as soon as
> power is
> > > > removed from the servo.
> > > >
> > >
> > > > Kim Lux <lux@d...>
> > >
> > >
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> http://groups.yahoo.com/group/jobshophomeshop I consider this to be a sister site to the CCED group, as many of the same members are there, for OT subjects, that are not allowed on the CCED list.
>
> NOTICE: ALL POSTINGS TO THIS GROUP BECOME PUBLIC DOMAIN BY POSTING THEM. DON'T POST IF YOU CAN NOT ACCEPT THIS.....NO EXCEPTIONS........
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Kim Lux <lux@...>