Re: LARGE Gantry table

Les,

The reason you and Bob are both right is that Chris did not mention
the one really important issue left...

Speed. You CANNOT discern drive size/type needs without adding this
into the figuring... And even if you know speed, you still need to
know how quickly this speed must be attained and reduced; i.e.,
accel/decel values...

There IS a hint in his message though. The word plasma and cut are
both there in the sig, so I'd assume we're talking a fair bit of
spped. Which would "lean me" toward your assessment, and away from
Bob's...

But for now, the question is answered not by "G" or "C", but by D-not
enough info given for a correct answer<G>

Ballendo





--- In CAD_CAM_EDM_DRO@yahoogroups.com, "Leslie M. Watts"
<leswatts@a...> wrote:

> Heh. Confused Chris? My friend Bob Campbell said a Gecko would
> handle it. I said it would need something bigger.
>
> To put things in perspective my 1000 lb gantry IS run by a Copley
> 412 which is about the same as a Gecko in power. So Bob is

absolutely

> correct for the weight you asked about.
>
> I just think that a 20 ft gantry will be much more massive than my
> system. Things tend to go up in mass as the cube of length for

equivalent

> stiffness. Sometimes even more. A finite element structure analysis
> can define this in the design stage.
>
> Les
>
> Leslie M.Watts
> L M Watts Furniture
> Tiger Georgia USA
> (706) 212-0242
> http://www.lmwatts.com
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>
>
> -----Original Message-----
> From: Robert Campbell [mailto:bob@c...]
> Sent: Tuesday, March 09, 2004 6:09 PM
> To: CAD_CAM_EDM_DRO@yahoogroups.com
> Subject: Re: [CAD_CAM_EDM_DRO] LARGE Gantry table
>
>
> Chris,
>
> You will defiantly need a servo system. I would think that a Gecko

drive

> would do it.
>
> You may want to post on the Gecko drive list.
>
>
> Bob Campbell
> Bob@c...
> www.campbelldesigns.com
> Breakout board
> THC board sets
> CNC router plans
> Stepper Motors
> ----- Original Message -----
> From: "cutthroatplasmaco" <cutthroatplasmaco@y...>
> To: <CAD_CAM_EDM_DRO@yahoogroups.com>
> Sent: Tuesday, March 09, 2004 3:52 PM
> Subject: [CAD_CAM_EDM_DRO] LARGE Gantry table
>
>
> > Can someone point me in the direction of suppliers for

motors/drives

> > for LARGE gantry machines... I'm talking 20'x40' cutting area. Off
> > the top of my head, I'm guessing the gantry might way a half ton

or

> > more. I'm very familiar with smaller steppers/servos, I just don't
> > quite understand where/what route you take when talking about

large

> > machines that need significant torque to make a 1000lb gantry

change

> > directions on a dime. It seems you need an ac servo that would run
> > off of signicantly more power than a gecko or similar can provide.
> > Any help/links would be appreciated.
> > Thanks,
> > Chris
> >
> >
> >
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> http://groups.yahoo.com/group/jobshophomeshop I consider this to

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there, for OT

> subjects, that are not allowed on the CCED list.
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