Re: Servo and electronics selection

Your machine looks a lot more powerful than the one I'm building. I
am going to use EMC when I get that far. I am driving the nut instead
of the ball screws though. I will synchronize the two x axis ball
nuts by using a single geared driver. Thanks for the transmission
specs, I can use them. Are you happy with your motors? How much did
you pay for them and aren't they a little overkill? Why did you
choose them, because of their simple wiring? Are you only using the
tach as feedback ? How did you keep your mounting base from racking
during the build? I used the MIC-6 plate as a permanent jigging
fixture. I hope you publish your experience with EMC soon.

Thanks

--- In CAD_CAM_EDM_DRO@y..., "Les Watts" <leswatts@r...> wrote:
> Sounds like a big machine!
> Mine is of similar capability and was also shop made. It
> cost a big chunk of money and time for the mechanicals.
> There is a link with pictures on my engineering page
> in the signature file below.
>
> A commercial control would be the quickest way to get the
> machine making chips.
>
> I am using EMC BDI, Copley 412 amps, Servo To Go II
> and a K6 pc to run mine with SEM brush dc motors.
>
> I am running with acceleration set at 20 or so in/sec^2
> so the 1000 lb gantry zips around like an old plotter
> pen. My max rapids are set to 600 in/min. At max
> acceleration instantaneous current is 60 amps if all
> three axes blast off at once with a load.
>
> I use an external e-stop circuit I designed. A schematic
> is on the web page.
>
> I can do a run on my servo sizing program if you will give
> me your machine mechanical details (ballscrew size and
> type, moving mass, friction estimates, etc). This will tell
> you what type and size of motor/amp will work well. I
> have lots of extra large servos if you need some but they
> may or may not be the right parameters for you- It depends
> on what the program says.
>
> Do you have any pictures of your machine?
>
> Les
> Leslie Watts
> L M Watts Furniture
> Tiger, Georgia USA
> http://www.rabun.net/~leswatts/wattsfurniturewp.html
> engineering page:
> http://www.rabun.net/~leswatts/shop.html
> ----- Original Message -----
> From: "kdoney_63021" <kdoney_63021@y...>
> To: <CAD_CAM_EDM_DRO@y...>
> Sent: Friday, April 05, 2002 9:49 PM
> Subject: [CAD_CAM_EDM_DRO] Servo and electronics selection
>
>
> > I am finally to the stage of selecting my electronics and motors
for
> > a 3-axis gantry I have been building. I have spend many hours and
> > thousands of dollars in the mechanics of this system and although
I
> > have been researching servos VS. steppers, DC brush and
brushless, AC
> > with DSP control, even VSRM's, I have no idea what would be the
best
> > path.
> >
> > The machine is 8' X 8' X 2' with ground ballscrews and preloaded
nuts
> > on all axes. The slides are hardened and ground 1" shafts with
linear
> > bearing. These are attached to 2 - 4' X 8' MIC-6 tooling plates
with
> > machined fasteners.
> >
> > I am more interested in precision than speed. Although I have been
> > able to buy the items I've needed so far, I don't want to spend
any
> > more than I have to. I have done my own machining to save money
and
> > now don't want to just through money at the problem. I want the
> > system to be general enough to handle any job thrown at it up to
> > milling 1/2" mild steel.
> >
> > I will be selecting the software later.
> >
> > Any help or suggestions will be appreciated.
> >
> >
> > Addresses:
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> >
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reach it if
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> >
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