"Pete C." wrote:

Karl Townsend wrote:

On Thu, 11 Nov 2010 20:38:48 -0500, "Pete C."
wrote:


Karl Townsend wrote:

The hydraulics came to life on the mill today. Only one leak right at
the base of the pump,about 6-10 drips per second. I can pee faster
than that, most days. I'm guessing parts would be impossible, the pump
name and any numbers are all written in jap. I'll make up a real nice
catch pan and run it with the leak for now.

I'm getting 700 psi at the pump. I assume that's enough pressure??

There are two gauges on solenoid cabinets below the tool changers that
have lammacoid labels calling for 500 PSI and that's the reading.

There is another gauge clear on top of the machine that calls out 560
PSI and its reading 500. My guess is this is the all important counter
balance unit. Anyway, I tried to tighten a relief valve adjust screw
and it won't budge. So, I started to undo the base. Then I decided to
stop and ask, "Is a spring and ball going to fly out a this thing?"
I'd never find it.

I looked at removing the whole unit. There's a plate on top of the
distribution unit that it bolts to. I decided to stop here too. Its
not leaking now. If I take it apart, there's likely some gasket to be
destroyed and never find another. How do you make up hydraulic
gaskets? Will some sort of silicone gasket goo hold it? Or will there
be some odd ball metric O rings?

Tomorrow, I'll try to move the Z ball screw by hand with the pump
running. If the force isn't high, maybe I should leave it alone for
now. I just KNOW I'm likely to break it worse.

Karl

Post a few pictures of the components in the dropbox and we'll be better
able to identify and assist.

The pressures sound reasonable, this is just counterbalance and moving
an ATC, not digging holes, so you don't need a lot of pressure. Will
that relief valve unscrew, i.e. is it stuck or locked with a lock ring?
Or is it bottomed out and a weak spring isn't letting it get quite to
the desired pressure? If the later you may be able to shim it a little
to get the pressure up to spec. Even at 500 PSI, you're picking up some
89% of the weight it's intended to take up so it's probably ok as it is.

There is a wide array of sheet gasket material available at your local
auto parts store for $5 or so. I just made a few gaskets for a tractor
hydraulic 3pt lift from one of the thinner Fel-Pro gasket sheets and
they are working fine. They cut easily with a utility knife or x-acto
knife. Stick them on with some of the spray on gasket sealer and you
should be good to go. That tractor is old, but it still runs ~2,000 PSI,
so your 700 PSI system should be a piece of cake. Beyond that, you will
probably find that the Japanese stuff tends to use more O-rings than
gaskets. Harbor Freight has some decent O-ring assortment kits for
little $ and again, on a 700 PSI system they should do just fine.

Thanks for the advice. My best guess is this was jammed so nobody
could F$%^ with it. I can see more room to tighten. I'm not going to
touch it for now cause its time for the servos to roar. Surely a 2+
horse servo can lift that much weight if speeds are low.

Say, I've got a device only IDed as "Z clamp". Its got larger wiring
than all the other 110 solenoids so it must use a bit for power but
its under 3 amp fuse for the Opto 22 output when I fired it.

Do you think it might be a spindle brake? I suspect not on a servo
spindle. Or maybe a clamp to prevent drift on the Z axis???

The later, it is to prevent the head from dropping on power down when
the counterbalance hydraulic pressure is gone. It will be a
power-to-release type brake, and must be powered after you have
hydraulic pressure and before you try to move the Z servo.

Do you
think it might work "dead man"? That is the brake is normally on and
power holds it open? Figuring this out is first on the list for
tommorrow. I want to turn the spindle and Z axis by hand before power
is applied. I'd like to run it full axis on Z to verify operation of
limit switches.

You'll need to power that Z clamp to release it or the Z ballscrew won't
turn. You'll also need to have hydraulic pressure or the head will drop
to the table. Place a piece of soft wood on the table under the spindle
as a safety measure to prevent damage if the head does drop.


There's also a spindle "low" and "high" solenoid. Do you think maybe
one of these solenoids has to be energized to hold the spindle in that
gear? Right now, I've got three inputs for "H", "N", "L" on the
spindle speed. The "N" and "L" are closed and the "H" is open. The
print shows these contacts as NO so I may have a broke input here.
Would you guess shift spindle with it stopped?

Likely apply to shift the gear and can turn off once the input shows
it's in gear. No shift when stopped, typically runs the spindle servo at
very low speed during the shift so that the gears will mesh. N and L
closed may mean that it's partially shifted, not a broken input.

Er, Karl? You aren't stuck in the shop with your foot pinned between the
mill head and the table are you?