Re: [CAD_CAM_EDM_DRO] Re: Servo controllers for table top machines.

On Mon, 18 Dec 2006 13:28:27 -0000, you wrote:

>Steve,
>
>Companies do not sell servo systems just to rake in higher profits.
>Servo systems perform better and are by far more efficient than a
>stepper system. Even the lowest cost VMC's use AC servo drives.

Some unscrupulous or narrow minded people will insist that you
absolutely need servos under any circumstances.

>Also, brakes are used often in vertical load applications. Ballscrews
>can be efficiently backdriven so when power is cut off, there is an
>automatic spring brake to keep the Z axis from falling. High end
>VMC's use a gas strut to do the same thing.

Absolutely dependant on the pitch of the screw. Try it with a fine pitch
ballscrew, it wont move.

>I'm not sure why you are against servo systems??!! They are indeed
>harder to setup and tune, but they work very well and have been proven
> to be far superior to steppers in high performance systems.

I'm not against them, they are often just not necessary when a stepper
can often do the same job at much less expense.

Read Mariss's post same thread....

Steve Blackmore
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