Re: [CAD_CAM_EDM_DRO] Moog Hydrapoint

stirlinguy wrote:

> Hi,
>
> I have acquired a Moog Hydrapoint (full hydraulic Bridgeport with
> tape reader) NC mill and am pondering the possibilities for CNC
> control.
>
> I know some people have ditched the hydraulics and gone with ball
> screws and servos. That seems like the most straightforward approach
> (to my mind, anyway). But, I was thinking that if the machine can
> already read tapes that setting up a computer to send signals
> emulating the tape could be done. Any thoughts?

It depends. Apparently, the Cincinnatti hydro-tel (I think that's what
they called it) had a totally hydraulic/pneumatic control, with a hydraulic
velocity DAC with a series of holes graduated in 1:2:4:8:16:32 etc.
areas. Not a good candidate for electronic upgrade.

No doubt the Moog has Moog proportional servo valves, which are
the industry standard. If they are in good condition, you can drive them
with linear signals from a velocity error amp, essentially a servo amp,
but the power amplification is done in the servo valve.

You should know that hydraulically-operated machines consume
HUGE amounts of power, require people 30 feet away to use ear
protection, often require water cooling of the hydraulic pump, wear
out VERY expensive hoses frequently, and are a general pain in
the rear. Also, if a high-pressure hose bursts while you are
nearby, the results can be FATAL! Pinhole leaks at 1500 PSI
can inject oil under the skin, causing an elioma (I think I spelled
that right) which can cause permanent disfiguration even after
surgery. Unless you will keep the machine in tip-top condition,
I would STRONGLY suggest you do NOT keep the hydraulics.
This is not a place for deferred maintenance.

> My reasoning for this is that the machine already knows how to move
> x, y, and z through the hydraulics, so why not use that
> functionality? (And save some cash!)

If this machine uses ballscrews and hydraulic motors, it would be MUCH
better to replace the hydraulic motors with servo motors.

If it uses cylinders to move the table, then a ballscrew conversion
would be a substantial expense. I would still go that way, rather
than messing with the hydraulics.

Jon