QUICK-TURN 15 Turret index won't index

[cnctoolcat]

I think the motor is designed so that when the turret is clamped, the motor can not rotate.

Maybe the rebuilders did something to cause the motor to malfunction by not rotating when the turret is unclamped?

How are you checking the motor on the bench without some type of manifold to bolt it to?

 

[Proboss]

If I remember there's a rotary valve on the end of the actual motor that sometimes gets a hairline crack in it that would cause this problem. Just remove the end plate from motor and you will see a dogbone shaped shaft that drives this rotary valve. Remove the valve and inspect it under a magnifying glass.

 

[E-Stop]

OK, we put everything back together and we are right where we were a month ago. We've run out of options and everything seems to be working as it should. The only unknown at this point is that we are not sure that the motor was rebuilt properly.

Here is our next step. We are going to run overtime to get a few days ahead on our production schedule for the sister to this lathe. Then we are going to pull the hydraulic motor out of the 'good' lathe and put it in the problem lathe.

This should tell us if there is a problem with the motor or if we need to look somewhere else. I'm hoping it is a bad motor because I really don't know where else to look. And the motor is still under warranty.

I don't like cannibalizing the good lathe. Seems like whenever we do something like this we introduce problems into the 'good' machine. It might be another week before we can afford the break in production to make the swap.

 

[E-Stop]

cnctoolcat wrote--
How are you checking the motor on the bench without some type of manifold to bolt it to?

We are leaving the manifold hooked up to the end of the motor so the hydraulic lines and solenoid valves are still attached. With the motor on a bench, the two ports on the manifold that supply oil to the clamp/unclamp are open. We just took a metal plate and C-clamped it over the holes. At that point we can activate the CW/CCW valve and make the motor rotate.

Do you think by restricting the oil flow thru those ports that we are not getting an accurate test of the motor?

Proboss wrote--
Just remove the end plate from motor and you will see a dogbone shaped shaft that drives this rotary valve.

You don't know how many times I just wanted to take that motor apart. But doing so will void the warranty. And at $3,000 for the rebuild, I don't want to take that chance.

 

[RyanV]

That rotory valve is the distributor I was talking about. If thats not doing its thing your kaput. 6K isn't sounding to bad now after all your down time. But, great idea on changing it out with the other one from another machine. I call that technology sucking Peter to pay Paul.

 

[wippin' boy]

know just how you feel on the swapping of parts
but not as risky with mechanical as electrical

what does the rebuilder say about your bench test


have you tried replacing that solinoid valve that controls rotation?

i'd speculate the couple hundred bucks before going after good machine

 

[E-Stop]

Hopefully we will be caught up enough by mid-week to make the swap. I'm not getting my hopes up. But at least we can pin-point (or eliminate) the motor as the cause.

wippin' boy--

The rebuilder says that the way we bench tested it should be sufficient except that we did not have it under load. And as far as the solenoid valve, we already swapped it out with our other lathe and have determined that the valve is working properly. As a matter of fact, we never switched them back. But when we swap the motors later this week, we're going to move the entire unit--- manifold, solenoids and all.

 

[E-Stop]

Well, we finally got far enough ahead on our work that we could shut the other lathe down and do the parts swap. We pulled the hydraulic gear motor, complete with manifold and solenoid valves, from both machines and swapped them.

The problem stayed with the machine. The hydraulic motor that we had rebuilt works just fine on the 'working' lathe and we get the same symptoms as before on the 'broken' lathe.

We've still got a problem and now we know where its not. Just gotta figure out where it is.

 

[E-Stop]

I've got a question

There's a plate (about an inch thick) that the hydraulic motor bolts on to. There are 4 bolts that hold this plate to the main casting. About midway between the 2 bottom bolts there is a cutout in the plate and there is an eccentric pin that bolts into the casting. By rotating the pin, it looks like it may shift the position of the plate. But the plate can only be shifted about .010 because of the tight fit in the bolt holes. And any 'precision' shifting done on the plate would be lost with the amount of bolt hole slop when bolting the hydraulic motor to the plate.

Anyone know the real function of this eccentric pin? It got moved by accident once and we think we put it back real close to where it was. It just doesn't seem that its function is very important.

 

[wippin' boy]

about now i would grab a roll of wire and redo everything from the cabinet to the turret
could be a lost nuetral is why your showing power at device but it's still not a complete circuit.

 

[cnctoolcat]

The eccentric pin determines the fit, or backlash, of the gears when assembled. It may be the pin is forcing the plate to bind the gears upon assembly. If the gears mesh too tightly, this may prevent rotation.
This would be my guess at this point.

 

[wippin' boy]

i agree with the pins purpose
but i dought the pin took this thing down
you'd be hearing the hydraulics load up and you would at least see it trying to move

 

[routlaw]

You say you have a QT15. I assume that it has a T-2 control.
The quickest way to check turret indexing is to manual (with a small screwdriver) activate the single ended solenoid and hold. The turret should unclamp; this causes the cam follower to be removed from the detent in the face cam caused by the movement of the throtle valve to wide open. This unlocks the motor. This also causes oil to be ported to the unclamp cylinder. Remembering to keep the single ended solenoid depress; now depress one end of the double ended solenoid. The turret should rotate. To stop; release the single ended solenoid and when turret stops, release double ended solenoid.
If turret does not move check the cam follers on the dog shaft that rotates the geneva cam. possibly broken followers or gear (this can be caused by a missalignment between the geneva am and the dog shaft.

 

[routlaw]

P.S Don't forget to remove electrical plugs from solenoids

 

[E-Stop]

THANKS YOU EVERYONE FOR THEIR INPUT

We finally got it working

It would take me several pages to explain all of the procedures and tests we have done on this lathe. I now know more about the inner workings of that machine than I had ever wanted to. Basically, we disassembled practically everything and put it all back together. More than once. And it still didn't work.

So we sat down this morning, as a group, and tried to retrace and think thru everything we had done. It all started when we had a couple of hydraulic hoses go bad and had to replace them. The two that go into the manifold on the back of the motor. dcrace asked early in this topic about the hoses being reversed and I replied that they were on correctly because they were color-coded but we switched them anyway and nothing changed. So we figured that was not the problem. (We only switched the ones that were replaced)

But as we were going over everything, the guy who replaced the hoses mentioned that he removed two other hoses (upline from the busted one) to make installation easier. We didn't know this until this morning. When we compared those lines with the ones on the other machine, they were reversed! Switched the lines around and all is working great.

We've been down for 10 weeks and spent $3000 to rebuild a motor that may not have needed it. And easily over 100 man hours working on it.

Thanks to everyone for their input. Especially to dcrace who had the correct solution. We just didn't look far enough up the line ----- to a spot where we didn't know we had disturbed.

 

[wippin' boy]

alls well that ends well

hope the boss feels the same

 

[cnctoolcat]

The guy who switched the hoses by accident caused a lot of unecessary downtime, and out of pocket expense. He needs to be told so.

He, and anyone else who might work on a machine, needs to be trained properly, so they can at least disconnect/reconnect a couple of hydraulic hoses without crossing them up.

Glad you got the 'ol girl goin'. I have 2 '88 QT15's I run every day.

 

[rotator]

similar QT15 turret problem

I found this thread after experiencing a lot of the same things. We had our hydraulic motor rebuilt, replaced the encoder, replaced (temporarily) the I/O board that reads the encoder, etc. The turret was stopping occasionally at some place in between stations, usually the same place. Decided it was a mechanical thing, took it all apart. The ID of the clamp piston looks like it is designed as a bearing, with spiral grooves. But if you tighten the nut holding the turret on, it will clamp the piston so it will rotate with the turret. Mazak and others I have asked cannot say what the procedure for tightening the nut is. Nut is split with two screws to jam it so it could be set to not quite tight and set there.
Our piston ID was scored up from little bits of steel broken off the spline where it is faced off just before it meets the the turret. I thought that if the shaft is rotating in the bearing, then this might be the cause of our stopping.
When it stops, we can give it a shove and it will go to the next station and clamp, as if it just didn't have quite enough torque to make it past a resistance.
Does anyone have advice for tightening the nut?

PS I am sure we do not have reversed hoses.

 

[wippin' boy]

i have allways tightened these nuts as tight as i could get them

 

[ricardo saul garcia]

metroe esta salindo esta alarma 272 turret index exceed time al jirar la torreta de un torno mazak 15ms alguin que me pueda alludar