Re: replacing feed screw with a hydraulic cylinder

Hello Friends,
I had in mind to change my hydraulic copy lathe to CNC. But everybody
I consulted said: Better not because its way it becomes more expensive
than servomotors and damn inacurate.
I didn´t believe until I made a test with a clients proportional servo
valves.
Now I second the warning:
Too inacurate!
Too Slow!
Pretty expensive!
Oscilation (0.02mm on radius!!!!)!
Trouble with dirt!

The day I may convert my lathe You can be sure I will kick out the
pistons for ball screws and servos.
Good luck
Sven Peter

--- In CAD_CAM_EDM_DRO@y..., Marv Frankel <dcdziner@p...> wrote:
> 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
>
> ----- Original Message -----
> From: "Ray Henry" <rehenry@u...>
> To: <CAD_CAM_EDM_DRO@y...>
> Sent: Saturday, November 30, 2002 6:28 AM
> Subject: [CAD_CAM_EDM_DRO] Re: Re: replacing feed screw with a
hydraulic
> cylinder
>
>
>
> > From: "blown_mgb_v8" <jblackwood5@i...>
> > Subject: Re: replacing feed screw with a hydraulic cylinder
> <s>
> > So here's the question(s), What would be suitable for retrofitting
> > the z axis (quill), what is needed to drive the steppers, can an
old
> > P-90 IBM clone PC be used to run it, and what software is
available?
>
> Hi Jim
>
> Yes the quill can easily be fitted with ball screws because there is
a
> yolk that extends parallel to the x axis from each side of the
quill.
> That's where the air-over-hydraulic cylinder for z is attached.
>
> Ray
>
>
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