[orbets]

Sorry for the lengthy explanation.
We are getting a stop alarm during the punching sequence showing "OIL PRESSURE"
The pump pressure slowly drops from 22Kgf to 15Kgf and the stop appears.
On smaller tools, we are able to punch 20-30 hits without a problem, but not above that.
When we switch to a larger tool, we are only able to punch 4-5 hits before we get the stop.
We can easily see the gauge moving up and down during the punching, but if the machine is in any mode other than F4 it appears that the pump can not keep up.
Pilot pressure remains consistent @ 13.5Kgf.
The filter indicators are not going into the red zone, so we are assuming that they are fine.
The oil level is reading above 3/4 on the sight glass, so again we assume that it is not starving for oil.
There is now cavitation noise coming from the pump.
The top valve has been opened a number of time to bleed potential air out of the system.
We do see some milky oil (about 1 inch at the top of the level) in the sight glass, and is assumed that there is some air still in the oil.
This should not be enough to be causing this sort of problem.
The gauge slowly drops between each hit and recovers depending on the program, but in F3 or faster, the pressure drops quickly to 15Kgf.

We did do a test to see how quickly the pump pressure drops when the machine is turned off.
From 22Kgf, the gauge slowly drops (about 7 seconds) to 7Kgf and then goes to zero immediately.
The accumulator bladder was change about 18 months ago and recharged about 6 months ago.
Any possible thought about what could be wrong?
Thanks.

[Pitre]

Sorry for the lengthy explanation.
We are getting a stop alarm during the punching sequence showing "OIL PRESSURE"
The pump pressure slowly drops from 22Kgf to 15Kgf and the stop appears.
On smaller tools, we are able to punch 20-30 hits without a problem, but not above that.
When we switch to a larger tool, we are only able to punch 4-5 hits before we get the stop.
We can easily see the gauge moving up and down during the punching, but if the machine is in any mode other than F4 it appears that the pump can not keep up.
Pilot pressure remains consistent @ 13.5Kgf.
The filter indicators are not going into the red zone, so we are assuming that they are fine.
The oil level is reading above 3/4 on the sight glass, so again we assume that it is not starving for oil.
There is now cavitation noise coming from the pump.
The top valve has been opened a number of time to bleed potential air out of the system.
We do see some milky oil (about 1 inch at the top of the level) in the sight glass, and is assumed that there is some air still in the oil.
This should not be enough to be causing this sort of problem.
The gauge slowly drops between each hit and recovers depending on the program, but in F3 or faster, the pressure drops quickly to 15Kgf.

We did do a test to see how quickly the pump pressure drops when the machine is turned off.
From 22Kgf, the gauge slowly drops (about 7 seconds) to 7Kgf and then goes to zero immediately.
The accumulator bladder was change about 18 months ago and recharged about 6 months ago.
Any possible thought about what could be wrong?
Thanks.

hi orbet,

do you still have the problem with the machine..?

let me know.

thanks.

[orbets]

hi orbet,

do you still have the problem with the machine..?

let me know.

thanks.

Hi,
Yes, we still have the problem but have been using in F3 & F4
Any thoughts?
Thanks.

[Pitre]

Check the Gas pressure in both the accumulators , smaller is on for smaller tools , bigger one is for bigger tools. if the Gas pressure is less you may have the situation you are in. if the gas pressure is ok then you may have to suspect the Servo Valves or Amplifier which malfunctions after heat is generated. Hope you have YUKEN valves and its Service available nearby. get it serviced by YUKEN.

[orbets]

Have narrowed the problem down to the "Shut Off Valve". We removed it to inspect and the solenoid itself appears to be intermittent and sending a signal whenever it wants. There is a small board with diode & 4 x transistors that is at fault. We can manually operate the solenoid and get the machine working when we take the board out of the system.
Looking now to have the board rebuilt, but chances are it's the solenoid that is (did) cause the problem.
The Shut off Valve assembly is a FUJI ENGINEERING LVS2-04G-A1D-NO-TB-6WA
Fuji seems to no longer exist or may just not have much info on the net.
Anyway, if someone knows where we can get a new one from or what replacement model is there, PLEASE let me know. Can't run the machine without it.
Thanks.

[mkshahateet]

Did you solve your problem? I have the same problem with my Pega 357..

[orbets]

I did.
On the front end of the machine, there is a cover that houses the relay board (pic Location on machine), If you see evidence (or still have mice like we did) living in that area, they have shorted out the board.
You need to remove that (and the mice) and get a local electronics guy to make you a new board (pic What you need).
As a temporary repair to get us by until the board was made, we simply removed the bolt on the back side of the solenoid and threaded in a T BOLT . (pic What it operates)
We still use the T BOLT it as it works well and the machine starts way better without having to start the oil pump at the same time.
Nothing as permanent as a temporary repair.
Loosen the T BOLT before starting machine. Once the machine is running, hand tighten the T BOLD and the oil pressure will build up in seconds and NC will be ready.
When shutting down, Loosen the T BOLT to release oil pressure.
Hope it helps.

[orbets]

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