Originally Posted by
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.