I have been working on a customers HMC. This is the worst case of hydraulic contamination I have ever seen. I have been replacing valves, flushing the system with new oil just to keep repeating it. I get one problem fixed and another area is shot. I need something that I can flush this system with. The valves I have taken apart are varnished and the insides have clumps of what looks like rubber cement. Any suggestions would be appreciated.

Have you had any OA done on the oil? This would be the first step to try and find the source of the contamination. A filter cart would be the next step to reduce the contamination in the system. If the oil is heavily contaminated then you may want to use a course filter to remove the bulk of the larger debris before finer filtration. Is moisture present?
If you're unsure, always get back to basics. Sometimes it's the simple things that make all the difference.
If you can provide any other details of this equipment then maybe some of the more knowledgeable members may give there two cents worth.

I think it would be first thing first that is start cleaning with filter cart and get the dirts cleaned and of course from tank to tank filtration and then look at the oil temperature as you say there is a vernish formation and look at the TAN and Viscosity values along with water and other wear particle.
May be this can help stabilsie systems.
regards
Arupanjan

This is a Mazak CNC Horizontal Maching Center. It is a closed system. The customer tried to rebuid the pump himself and that is what was causing the heat. I replaced the pump and have taken care of the heat problem. My problem now is the contamination in the system. The customer has never changed the oil and the machine is almost 20 years old. I have changed the oil out 2 times in the last 2 weeks. Upon inspection of the valves I found a substance that looks like cement glue. I need a product to put in the oil to loosen the contamination from the valves. The system does have a filter on the tank side. I appreciate the input.

There are probably several reasons for the gelling in you lubricant including oil. degredation and biological contamination which is carried into the oil by water. Machine tool oils often have problems with biological contamination. Your tank filters will be of little use in removing most of the contamination as you need finer filtration than they normally provide so an ofline system is recommended. Electrostatic filters and Ionizing filters have shown to be effective in removing varnish that has built up over long periods of time but they take time to work (consider it a permanant installation). To get rid of the gell you may need to resort to disassembling all servo valves and flushing or rodding out the all the fluid lines in the system. I don't know off hand of a solvent that could clear out the gell without repeatedly sticking up the servos until the system is clean. For flushing air compressors we often use a diester base lubricant which has a natural solventcy and cuts built up mineral oil varnish. You might check if a fluid like this is compatable with the seals and componants in your equipment.

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Originally posted by CNC Service:
I have been working on a customers HMC. This is the worst case of hydraulic contamination I have ever seen. I have been replacing valves, flushing the system with new oil just to keep repeating it. I get one problem fixed and another area is shot. I need something that I can flush this system with. The valves I have taken apart are varnished and the insides have clumps of what looks like rubber cement. Any suggestions would be appreciated.

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CNC Service
I feel that the problem you are facing is with valves during and after flushing the hydraulic systems. Normally during flushing it is advisable to remove the valves and fix dummy plates with suitable flow passages and flush the system.
After flushing replace the valves and run the system . Hope this helps.

Franky

Hi CNC Service,
You can try a product like EXXON Sysyem cleaner. You mix it @ around 10% with the oil. Then leave the system running, the problem is that it loosens up the sludge etc and brings it back into circulation so it will actually cause the system to plug up, unless you can filter out the crap before it goes through the servo's etc. Depending on the amount of build up in the nooks and crannies you might have to do this a few times until the system is cleaned up.
Tell your customer to smarten up in the future, change the oil. Sell him on oil analysis at least 1 time a year, this should help you to him to protect him from himself. I'm sure you'd rather be performing more meaningfull work that moping out the toilets.

regards........

Thank you, that is the information I was looking for.

Summit Industrial Products, Tyler Texas also has a product called Varnasolv that is designed for just this problem, it is also added at 10% and has the advantage of also being a lubricant as well. You can contact them at: (800) 749-1375

Thanks,

Allan Zieser

CNC Service,

You also can look for expert help, I mean with the right equipment to perform the job. There is a company in Texas, I know they deal with this type of problems, you can reach them al 281-367.1500 The company name is Lewco Contamination Control

CNC Service,

You need to go to the root cause. If this is a Machining Centre, probable cause is contamination with cutting oil. This could happen due to
1. Electronic failure, wrong pump triggerred.
2. Hydraulic system topped up with MW oil.
3. Line leakage

Many metal working oils contain chlorinated fats for better "Tool performance." Some EP soluble metal working oils may also contain Chlorinated compounds.

Pls revert with details of make and type of oil (Metal working oil) used.

Hussam Adeni

Dear Mr,

I just read your issue about the varnish problem. If you still need some help let me know.

Rene Steffens

hi friends . i am having problem with my CNC machine lubrication pump it not getting ratted pressure with the setting time ,pls sugguest me