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Mazak - SQT10MS - EATING hydraulic oil

mkalavitz

Aluminum
Joined
Sep 7, 2006
Location
Grand Rapids, MI
Hello,

Mazak SQT10MS

machining a bar only to come back to a red flashing light. The T32-3 control said something to the effect 'low hydraulic pressure'.

So, I checked the hydraulic oil and sure enough, it was low. Topped it off and started running.

Upon pulling the parts from the tray, I noticed that they seem to be oily. So, putting two and two together,

I assume that the hydraulic oil is somehow finding its way into the coolant tank.

There was a leak (looks like coolant, but wondering if it is coolant/oil) coming from the back edge of the turret. Leaks

slightly when running and a big leak when the turret rotates.

So, I pulled this little block off the bottom side of the turret head thinking that maybe I had a bad o-ring. Replace the o-rings and started running.

Seems to have helped the leaking a little bit, but wasn't long before I the hydraulics started making noise again.

Dang it! Low hydraulic oil.

So, I filled it back up and now trying to diagnose where the oil could be going to.

Does anyone know if the hydraulics have anything to do with this coolant block? It seems a rubber nose on the front of this block is supposed to close the coolant
passage when coolant is called for and then open when it is not called for or there is a turret rotation to a new tool. Do hydraulics push this rubber
nose in and out? Or, is it the coolant pressure that does this?

Where else could there be a hydraulic leak? Inside the turret somewhere? What rotates this turret? Hydraulic or electric?

Please let me know what other ideas you might have that I can look at. Need to get this machine up ASAP.

thx much

Mike

190513 - Mazak SQT10MS - Coolant Block 2.jpg190513 - Mazak SQT10MS - Coolant Block 1.jpg
 
Take all this with a grain of salt as I don't have your machine but I do have a QT8 made around the same time. Looking up your machine it appears to be of a similar configuration.
Mine had an identical issue. There is a hydraulic cylinder that pushes the turret in/out when it indexes. Once the cylinder pushes it out, an electric gearmotor turns the turret to the desired tool position. The O-rings in the hydraulic cylinder wear out and cause hydraulic oil to leak. Like you, I had a small constant leak from behind the rotating part of the turret that would suddenly gush out more oil when the turret indexed.

On my machine I was able to remove the rotating part of the turret and then disassemble the hydraulic cylinder to clean it and put all new o-rings in it. I posted a thread about it here: https://www.practicalmachinist.com/...et-hydralic-seal-replacement-1989-qt8n-351888
Yours is probably a somewhat different internal design, but if you examine parts books for your machine you should be able to find what seals you need to replace. Mine were all standard size o-rings so I didn't have to buy anything from Mazak. Again, YMMV. Replace the big rubber wiper sealing the turret edge while you are in there, this you will have to get from Mazak.

This video from PM member ewsley might also help, it's a different manufacturer machine but looked pretty similar to my Mazak. You shouldn't need to actually align anything, but it's a good visual reference for what this design turret looks like inside. YouTube

The block you removed looks like my coolant block, mine is spring-loaded and has a hard plastic nose that seals against the turret backside. It's not actuated by anything, other than spring pressure. I had to get a new plastic nose for mine as it wore out and leaked coolant. I don't think it's at all related to your oil leak, but again I have a different machine so YMMV.

Anyway hope this helps, and I also hope someone with experience on your specific machine chimes in.
 
Thank you for taking the time to respond.

Based on my observations, I think you are spot on. I need to tear into this dang thing.

I just went out and looked at the hydraulic level, and it is down probably 1+ gallons just from idling. No turret movement or anything. Is this possible to lose
oil when the turret isn't even moving? Hydraulic pressure on the turret clamp leaking?

It sure seems like I lose it this fast or faster when rotating the turret.

Thanks for the advice. Time to get dirty. Always happens at the worse time possible!

Thanks again..

Mike
 
those turret coolant blocks will absolutely blow a tank of oil out in an hour
pull the brass piston out and replace the o-rings(p10 maybe).
once they start wearing out that oring ring it can become chronic so keep a bag in stock
 
Thanks Wippin Boy. Yes, this is the very first thing I did. I thought it was the problem also. But, it turns out, on this machine, the coolant block does not use hydraulic oil to actuate the piston. It is spring loaded against the back side of the turret.

BUT...I FOUND THE PROBLEM! For documentation purposes, here it is....

I came in the shop this morning ready to start tearing into the turret. I was surely expecting that the turret actuator clamp seals where blown.

I cleaned the machine up of chips and pulled the coolant tank out. For further investigation, I cleaned the floor up under the machine and laid out a big sheet
of dry brown paper. I turned the machine on and waited for it to leak. I wanted to see it with my eyes. Rotate the turret a bunch and nothing. Hmmm..

Clamped and unclamped the rear jaws and heard a 'squirt' noise. WHAAAAT? Yes, moments later a nice puddle of oil under the machine under the rear head.

I pulled the end cover off from the machine and found a leak squirting out every time the rear jaws where actuated. It turns out that the rear draw bar actuator
had a leak. It was missing 3 of the 6 SHCS's and the other 3 were loose. Replace all of the screws and loctite them.

Tested and BOOM! Problem fixed. Now just cleaning up and replacing coolant.

So glad I did not dig into the turret prior to finding this problem. Hope this helps someone. See attached pictures.

If anything else changes, I will continue this post.

Thanks for the help!

Mike190514 - Mazak SQT10MS - Rear Chuck Hydraulic Leak 1.jpg190514 - Mazak SQT10MS - Rear Chuck Hydraulic Leak 2.jpg
 








 
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