Re: Re: Ballscrew Installation issues

Andrew,

I would make sure that the X and the Y assemblies have the same number of
turns per inch.

BTW, I just got my dealer copy of ModelMill in. I plan to go to Colorado
for training next month.

Bob Campbell

----- Original Message -----
From: Andrew Werby <drewid@...>
To: <CAD_CAM_EDM_DRO@onelist.com>
Sent: Monday, February 21, 2000 2:50 AM
Subject: [CAD_CAM_EDM_DRO] Re: Ballscrew Installation issues


> From: Andrew Werby <drewid@...>
>
> I'm shopping for a few good used ballscrew/linear motion assemblies
> (preferably already assembled) for a router I've got in mind, and I was
> wondering: do these have to match in screw pitch and inches traveled per
> revolution? While I'd prefer to have everything the same, it seems
> difficult to procure matching slider assemblies. Is it okay to get these
as
> they come up, and trust that I'll be able to reconcile their differences
in
> the software setup? Or should I hold out for matching parts? Does this
vary
> between control systems?
>
> What about motors? Is it possible to combine different stepper motors in
> the same machine, and expect them to operate in tandem? Is it any easier
> with brushless DC servo/encoder combinations?
>
> Andrew Werby
> http://www.computersculpture.com
>
> Roger Brower <rbrower@...> wrote:
> Subject: Ballscrew installation issues
>
> stratton@... Wrote:
>
> Subject: Ballscrew installation issues
>
>
> >With a .200 lead screw and a 200 step/r
> motor I need 2:1 reduction
> just to get steps of .001, but am
> planning on going for .0005 or
> .00033 if I use a 10 tooth driving a 60
> tooth.
>
> You may well end up using a half step
> driver for increased torque and reduced
> resonance reasons.
> A 200 step per rev motor is 400 discrete
> half steps per rev.
> Also note the McMaster 5/8 screws are
> 31/64" pitch; with 1:1 drive, I
> calculate: 1.8 deg per step motors, 200
> steps per rev, 400 steps per rev half
> step mode;
> 13/64" screw lead =(.203125 inch per
> rev, or 4.9230769 rev per inch)
> So: .203125 / 400 = ~1969(.2792) steps
> per inch for ~.0005 resolution.
>
> Am I in some kind of trouble with this
> odd number (vs 2000)?
> I know CNCPro can't use the decimal
> remainder (.2792) on steps per rev
> setting.
> I didn't want to gear it down and lose
> the travel speed potential or, God
> forbid, lose steps by trying to spin the
> motors too fast...
>
>
>
> Andrew Werby - United Artworks
> Sculpture, Jewelry, and Other Art Stuff
> http://unitedartworks.com
>
>
>
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