Re: [CAD_CAM_EDM_DRO] Re: 4th Axis Concept (long)

Hi Chris, Roger,

If you use the servo, and also free-run it as a spindle motor, I'd
suggest using an "optical interrupter switch" (or hall effect sw) to
"find home". You should be able to switch control back to servo, and
"drive" it back to this "home".

Alan KM6VV


vrsculptor@... wrote:

>
> --- In CAD_CAM_EDM_DRO@y..., datac@l... wrote:
> > In the following explanation, picture in your minds 2 motors
> driving a Sherline or similar Lathe spindle, First motor: a dis-
> engagable stepper, The Other: A traditional spindle drive motor....
>
> Chris,
> Interesting idea. If I where to do this I would use a servo motor
> instead of a stepper. A servo motor with encoder can be controlled
> with a Gecko 340 using step and direction input just like a stepper.
> When in lathe mode just switch out the controller and apply DC
> directly to the servo. You could get the RPM you need without having
> to clutch a motor in an out.
>
> There is still the problem reseting the piece to zero. I think this
> could be handled by turning off the power and rotating the shaft by
> hand to a known position. A fixed position could be established by
> resting an arm, attached at a right angle to the 4th axis shaft, on
> the top of a 1-2-3 block or some such.
>
> Roger
>
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