Re: [CAD_CAM_EDM_DRO] Re: hydraulics with CNC

In a message dated 6/7/2004 11:18:59 AM Eastern Daylight Time,
eexgs@... writes:

I wonder if some
simple electronics could be made so that the hyraulic ram would act
like a stepper. In other words a step pulse comes in and the ram in
turned on until a certain number of pulses have been received from
the encoder then it is turned off. Assuming you don't send the
pulses too fast it would work OK. It also assumes that the ram
doesn't need true servo control to hold it in lock.

Just a thought, don't know enough to say much more.


I must have missed the original post on this. Is the application one where
you wish to position a hydraulic piston in specific locations but not the
full travel each time. You want to be able to stop it at various locations I
assume. There are special valves for this purpose, they keep the pressure
constant on each side of the piston until a move is called for and then they
release the pressure on one side and apply it on the other until told to turn
off. Then the fluid pressure is applied, again, equally on both sides of the
piston. This holds the piston in the existing position. I haven't used these
in a hydraulic application but have used them in pneumatic applications but,
I was using a linear encoder for feedback so that the control knew when to
turn off the signal. I don't see why you couldn't do the same thing with a
stepper, just control the number of pulses as mentioned.
We used Keystone pneumatic valves and solenoids on these projects and I
don't know if they even make a hydraulic version but I would think someone, like
Parker, would make control valves of this nature.
Randy Abernathy
4626 Old Stilesboro Road NW
Acworth, GA 30101-4066
Phone / Fax: 770-974-5295
Cell: 678-772-4113
E-mail: Cnc002@...

I furnish technical support, repair, and other related services for your
industrial woodworking machinery. My background as Senior Service Engineer for
the SCMI Group for nearly fifteen years with factory training, combines with
my extensive background in electronics, mechanics, pneumatics, electrical and
CNC machinery to offer you needed support for your machinery.


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