hydraulic queries

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
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
wrote in message

Stay away from the silicone gasket goo. phil k.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Karl Townsend wrote:

Next time you're at the store, get a white plastic trash can. Position it such that when the spring and ball fly out, they land in it. ;-)
Once, I had just bought a Lorcin .25 ACP, and it didn't have instructions as to how to take it down to clean it. The neighbor was visiting, and he showed me the secret combination, and in the process, some important spring and some other part flew across the room and under the desk. I threw the guy out of my house, but I _did_ eventually find the parts for my new (used) pistol. ;-)
So you'd probably find the spring and ball, if your shop isn't a pigsty. ;-P
I later sold the pistol for $25.00 more than I had bought it for, and didn't miss it. It was accurate enough, but lady-sized, and the slide rubbed on my finger-thumb web. )-;
Good Luck! RIch
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Karl Townsend wrote:

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.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
wrote:

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??? 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.
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?
Karl
l
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Karl Townsend wrote:

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.

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.

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.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
"Pete C." wrote:

Er, Karl? You aren't stuck in the shop with your foot pinned between the mill head and the table are you?
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
wrote:

I can't get the Z ball screw to turn for the life of me. I must be missing a lock pin or something. So, I just hired a CNC repair fella to come in and look at it. He'll be a week (or more) coming.
karl
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Karl Townsend wrote:

You powered the Z clamp to release it? And also had the hydraulics on to counterbalance the head?
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
...

Yep and yep.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Karl Townsend wrote:

Ok. You know there is quite a bit of expertise in this group, if you post some good pictures of what you're looking at to the dropbox we can probably help more.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
wrote:

I'll do that. Today, I'm taking the servo loose to see if that will spin around just a bit. This will show me if the brake is holding me, or the ball screw itself. it looks impossible to undo the servo coupling if I can't spin one or the other. I'll take the servo clear off if I HAVE too. Don't want to cause it must wiegh over 100 lbs. and its eight feet in the air with no easy way to get a lift near it. Accident just waiting to happen.
Karl
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Karl Townsend wrote:

The last time I did one of those (Fanuc 10M DC servo on top of a Kitamura) I got my thumb stuck under the flange and mumbled quite a few expletives while fumbling for a screwdriver to pry it off my thumb.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
This is an electric servo system, not weird hydraulic or anything like that?
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Ignoramus12083 wrote:

Yes, it's a standard servo. Not sure if DC or AC on his machine, but it's a big machine and thus a big servo, likely a 10HP model. Recall it also has hydraulic counterbalance for the heavy head.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Polytechforum.com is a website by engineers for engineers. It is not affiliated with any of manufacturers or vendors discussed here. All logos and trade names are the property of their respective owners.