Mazak QT15N Hydraulic pomp problem

[Zebovsky]

Hi guys,
I’ve recently changed the hydraulic oil in my machine (Mazak QT15N. I used the substitute oil Mobil DTE24 (HLP32). I’ve noticed that sometimes the pump is really loud at the beginning of work (during start-up). After a while, the sound fades away or disappears completely. What could be the problem? Is it the fault of the oil? Should I consider a repair of the pump? I attach some photos of the pump and a video with disturbing sound.

 

[noname777]

pull it apart. there is absolutely nothing complicated about the whole setup. The pump is a very basic vane pump configuration. Normally would last for a million of years. Than you have two bearings inside AC motor, they fail regularly.
Check suction filter inside of the oil tank as if it is blocked u might have a cavitation mode, which is very harmful for typical vane pump

 

[Zebovsky]

Hi, thank you for your answer. I only changed the oil, I did not clean the tank. It is possible that the filter inside the tank you are talking about is the cause of the problem and I should check it first to diagnose the problem. Could you please give me some tips on how to get to the tank? I'm not really a good mechanic.

 

[noname777]

I think u need to mark all hoses and disconnect them. After undo all bolts around tanks perimeter and try to slide it to whichever side it wants to move, as inside the tank there are still will be couple of drain pipes and suction port pipe with strain filter. I think.

p.s. try to play with this valve, on the top of your pump. The one you need to adjust your machine system pressure. See if low system pressure, say 3 Bar instead of 6 Bar makes a difference in acoustics noise.

 

[cnctoolcat]

Your main system pressure needs to be about 500 psi...it is set too high!

ToolCat

 

[Zebovsky]

Hello, I took your advice and reduced the pressure to 500 psi. The machine seems to run more "smoothly". I noticed a slight leak at the pressure adjusting screw. The pump makes disturbing noises when starting (I noticed it mainly when opening the jaw), after some time the sounds are getting quieter.

Ps. The pressure of 1000psi was recommended to me by a mechanic during the assembly of the machine.