Re: Re: replacing feed screw with a hydraulic cylinder

Ray, please do elaborate. I will have the machine here in a couple
days and would like to learn as much about it as I can. For
instance, since the hydraulic system is already in place, what would
it take to put linear encoders on the thing and replace the air
logic with a PC?

Jim

--- In CAD_CAM_EDM_DRO@yahoogroups.com, Ray Henry <rehenry@u...>
wrote:

>
> Hi Marv
>
> I was thinking that the title of this thread was backwards because

a Moog

> Hydrapoint like Jim wants to convert uses hydraulic cylinders for

axis

> movement. It seemed to me that Jim was wanting to replace these

with

> ballscrews.
>
> The stock position control of the hydraulic ram was not based on

fluid

> volume. Ram position was based on a set of air holes in a plate

that

> slid along with the ram. You could think of the air part as an

absolute

> linear encoder that used air instead of electrical impulses. If

that's

> not confusing enough, I could elaborate.<g>
>
> Ray
>
>
>
> > Subject: Re: Re: Re: replacing feed screw with a hydraulic

cylinder

> >
> > Guys,
> >        I've been following this thread, and although I've

never done

> > it, I wonder if the coefficient of expansion of the hydraulic

fluid,

> > would cause some accuracy problems? On a cold day, it would cut
> > differently than on a warm day, and would you have to reset your

Z axis

> > every time the temperature changed?
> >
> > Marv Frankel
> > Los Angeles