Re: [CAD_CAM_EDM_DRO] Bridgeport Milling Machines

> the cost of ownership is vastly less. Now, they are getting rid of
> hydraulics on aircraft, as they can do many things more reliably
> that with hydraulics.

Hydraulics, planes? Heck they're getting rid of the welding wire! The
Eurofighter / EF / Typhoon's body is a composite fibre of some sorts that's
glued, not welded. That is one fine plane, it's claim to fame being an under
five second 0 to take off acceloration using it's own engines (It's own
NOISEY engines I should say). That and it's vocal command system, auto
landing etc. I wonder if you can order it to fly you to the local gas
station? There is a Cobra helocopter for sale on Ebay right now, asking
price is half a million, 1 hour test flight is ~$2,500.

> I really don't think this is a practical solution at all. A much better

way is

>
> to replace the tracer valve with separate proportional hydraulic control
> valves, commonly called Moog valves. Be sitting own when you inquire
> about the cost of these valves. They go for thousands of dollars each!
> These valves have millisecond response, extremely small deadband, and
> a very linear relationship between current in the coils and flow to the
> cylinder. Your proposed lashup would not be able to come close to a
> properly set up proportional servo valve. The motors would have so much

lag

> that the system would be hunting .01" all the time. The working pressure
> in these systems (and in the tracer-valve systems, too) is probably

between

> 1000 and 1500 PSI.

I suspected the idea would not work from the moment I dreamed it up, it was
just a thought. Perhaps another way would be to make the tracer probe think
it's hitting the sides of the part to be traced so you don't have to muck
about with the hydraulics themselves? Does the tracer's table sit still and
the guy moves the probe by hand or does the tracer trace something sitting
on the end of the mill's table?

John H.