Re: [CAD_CAM_EDM_DRO] Re: replacing feed screw with a hydraulic cylinder

People have built hydraulic-activated machine tools for decades. All of
them had positive control by means of servo-valves. You pointed out the
major problems yourself, with fixed ratio pumping. How can these be
surmounted?



At 01:04 AM 11/6/02 -0000, you wrote:

>I've thought about hydraulic drive CNC for years. This may have
>already been discussed but my idea is to use a closed system with
>single shot pistons powered by solenoids or a motor driven cam. Each
>stroke of the piston would pump a metered amount of fluid from one
>side of the cylinder to the other kind of like a hydraulic jack. One
>stroke of the piston would equal a fixed amount cylinder travel. A bi-
>directional piston with check valves could be used to change the
>direction. Example: 1000 piston strokes could equal 1" of
>travel, kind of like a linear stepping motor. A stroke counter
>could keep track of the position. This system should work with
>stepper motor software. Some obvious negatives I can think of: Slow
>speed (?), piston seal leakage, temperature may change volume of
>fluid (?). Just thinking out loud but I'd like to hear what
>others
>think.
>
>--- In CAD_CAM_EDM_DRO@y..., "al5502" <telecomt@t...> wrote:
>> Did somebody try to get rid of the feed screw all together
>> and replace it with a hydraulic cylinder?
>> At the first glance it may present several advantages:
>> no backlash, big force at low cost.
>> Alex
>
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