Mori Lathe Turret Hanging on One Tool Only

2000 Mori Seiki SL-200SMC w/Fanuc 18i-TA/Mori MSC501

Lately I've been running a job with a fully loaded turret that keeps hanging up after the parting tool in No 8 slot. Not sure it matters, but this tool is thru coolant and has a very restricted coolant outlet. The turret works fine for all other tools. I've also held the program until residual pressure drops from the tool without it making any difference.

This is a servo driven turret with a hydraulic system that I'm pretty sure is operating or driving in and out a locking and/or position setting pin. The typical sound is clunk... spin to new tool... clunk. Especially noticeable when manually indexing one tool at a time. The clunks are definitely the hydraulics part of it all, as I can watch and feel the spool valve operating in back by the pump in unison with the sound.

During automatic operation I get the first clunk, then it hangs without any rotation. If I'm recalling correctly, on the screen in the buffer area are the MTN (Maintain?) and FIN (Finish) signals displayed. So obviously it's waiting for a finish signal. But here's the thing. To get out of the problem I go into Jog or Rapid Mode, which is needed for manual turret movement, and do a simple two button push that would normally advance the turret one space in either direction depending on which two of the three buttons are pushed simultaneously. What it does is it gives me the second clunk but no turret indexing. After that everything is back to normal until the parting tool in the program comes around again.

I can operate the manual turret controls in any fashion and it never misfires. I also created a looping program which ran in auto mode that indexed the turret two slots every three seconds. It just went on and on without a single problem. I re-wrote it to advance in the opposite direction and no difference.

Here is the code at the time of failure. Nothing here that should matter. It's the end of the parting tool and initiation of the next tool. I even got rid of the M00 to see if that mattered and no change. I also changed the next tool number to something else and that didn't matter either. This transition or tool change coding is typical for all tools so nothing new here.

G99G1X1.866F0.0035
G4P25
U0.02F0.01
M5
M9
G53X-2.
G53Z-2.

T0200(FACING)
M00(KNOCK OFF PART)
G20G40G54G80G97G98

G0Z-1.T0202

Other tidbits of potentially helpful or useless info.

The turret is bi-directional in auto mode but not in manual, except for when you do the two button simultaneous one station index routine.

I get some coolant leaking out of the let's call it crack where the rotating and stationary parts of the turret meet. Is this normal, or a sign that some internal seals need replacing? Should this be dry as a bone?

Anyway... this is a freak thing and has me stumped.

I do have all the books but no ladder manual.

My wild guess? Which doesn't completely explain the difference between auto and manual mode. I got a feeling it's something purely mechanical holding up the lock pin from full movement, and has to do with the weight distribution of the fully loaded 12 tool turret. I've got 3 each of dual Z and single X axis live tools loaded, and a couple heavy dual turning tool blocks. Nothing strikes me as lopsided looking at the tool distribution, but you never know.

Thanks for listening.

Dave

I have had internal geartrain on live toys hang the turret at times, but, since you are indexing away from a static tool - ???

Just fer grins, have you tried indexing away in the other direction?
Or - maybe it's not sure which direction to turn on a "closest" equazsion?

You are at 8 and going to 2 as I understand it?
That is same distance either way...
Maybe add a line between showing T500 or T1100?


------------------

Think Snow Eh!
Ox

MTN stands for Motion. It means that a motion command has been issued. The FIN says the PMC is waiting for an input to occur.

Ox said:

Just fer grins, have you tried indexing away in the other direction?
Or - maybe it's not sure which direction to turn on a "closest" equazsion?

You are at 8 and going to 2 as I understand it?
That is same distance either way...
Maybe add a line between showing T500 or T1100?

Click to expand...

Fer Grins? You mean shits and giggles? :-)

Yes I tried a different tool number and no change. Kind of a good point about the next tool being the same distance in either direction. Wouldn't it be silly if the damn thing was confused and couldn't stop thinking about it?

I'll try another number again, but what I think I might do is write a program that mimics all the tool changes without any machine movement. This would eliminate all factors that might be contributed to by movement or other machine actions. I'm about ready to tear this setup down, but before I do I want to try a few more things. Once I significantly change the turret setup I'll re-run the tool change mimicking program and see what happens. I still think it has to do with weight. Let's face it, this machine has made thousands of tool changes over the years. Maybe wear somewhere is causing the lock pin to hang up in this exact situation, but manages to sneak by and operate properly with another setup.

Speaking of wear, I'm still wondering about the coolant leaking in the crack between rotating and stationary turret elements. Is that normal?

Vancbiker said:

MTN stands for Motion. It means that a motion command has been issued. The FIN says the PMC is waiting for an input to occur.

Click to expand...

Aha... MTN means Motion. Learned one more tidbit of useful info. Thank you.

So what the machine is saying is the lock pin retract signal was given and answered do to a successful retract, which would then allow the turret motion command to the servo to be given, and that movement has not happened and that's what the control is waiting for? So it's a servo drive signal fault? How could that consistently happen in one location and not all the others? Too weird. If the lock pin retracted signal has been returned affirmative, then my hung up lock pin idea doesn't make sense.

On 2nd thought, could it be the MTN command is for the lock pin and that's what it's waiting for? I may be misinterpreting your answer.

I've got to spring for a ladder manual. I'm betting that could help in some way.

13engines said:

If the lock pin retracted signal ...

Click to expand...

I've never taken apart a Mori but they have a decent reputation. I'll go out on a limb and say this better not be no shitster 'lock pin'. Should be a curvic coupling.

Don't they give you parts books with these things ?

Sounds mechanical to me and you'll either have to take the turret apart to fix it or learn to live with this little 'quirk' ...

13engines said:

Fer Grins? You mean shits and giggles? :-)

Yes I tried a different tool number and no change. Kind of a good point about the next tool being the same distance in either direction. Wouldn't it be silly if the damn thing was confused and couldn't stop thinking about it?

I'll try another number again, but what I think I might do is write a program that mimics all the tool changes without any machine movement. This would eliminate all factors that might be contributed to by movement or other machine actions. I'm about ready to tear this setup down, but before I do I want to try a few more things. Once I significantly change the turret setup I'll re-run the tool change mimicking program and see what happens. I still think it has to do with weight. Let's face it, this machine has made thousands of tool changes over the years. Maybe wear somewhere is causing the lock pin to hang up in this exact situation, but manages to sneak by and operate properly with another setup.

Speaking of wear, I'm still wondering about the coolant leaking in the crack between rotating and stationary turret elements. Is that normal?



Aha... MTN means Motion. Learned one more tidbit of useful info. Thank you.

So what the machine is saying is the lock pin retract signal was given and answered do to a successful retract, which would then allow the turret motion command to the servo to be given, and that movement has not happened and that's what the control is waiting for? So it's a servo drive signal fault? How could that consistently happen in one location and not all the others? Too weird. If the lock pin retracted signal has been returned affirmative, then my hung up lock pin idea doesn't make sense.

On 2nd thought, could it be the MTN command is for the lock pin and that's what it's waiting for? I may be misinterpreting your answer.

I've got to spring for a ladder manual. I'm betting that could help in some way.

Click to expand...

Absolutely S&G's.
My bad, I forgot my Norse accent.

As for fluid coming out of the turret, ass_u_ming that you are meaning around the big diameter, I doubt that would be normal, but I don't have your machine, nor 100% sure where you mean, but I think that I doo. AND - I have one leaking there myself, and I will need to pull the turret as soon as I can have it down to figger out how it's getting oil there.

On a side note - my coolant has much lubricity in the mean time!


"Ladder Manual"

???

Meaning so that you can learn the codeing in the ladder?
Or docs on the ladder?
You doo understand that the Fanuc ladder is visible on the 18i eh?
.. and that the ladder is functionally color coded?


You keep mentioning a shot pin in the turret.
Shirley Mori didn't run a shot pin in any turret in 2000!

I would ass_u_me that you have either a 2pc or 3pc Hirth type coupling.
When the turret indexes (normally) and you hear a "pop" or whatnot...
... are you seeing lift in the turret top plate at all?
Like - Lift, index, re-seat?



OK - it sometimes, most times, or always gets stuck at this point of this program?

When it stops, can you index it away in JOG without moving the X/Z at all?

My guess at this point is that you have a prox "not" seeing that the top plate has "lifted", and is ready to index as soon as it sees it.
This would indicate that you may have a prox cable that has rubbed raw in the raceway somewhere, and it just happens to ground out or ??? at this exact spot.

The ladder will show you that.
You may need to refer to the drawings to determine which input value is your "turret up" prox, or - if you have a well written ladder, you may be able to read enough text in the ladder to tell which it is? I don't know how a Mori ladder looks.


--------------------

Think Snow Eh!
Ox


-------------------

Think Snow Eh!
Ox

Ox said:

When the turret indexes (normally) and you hear a "pop" or whatnot... are you seeing lift in the turret top plate at all?
Like - Lift, index, re-seat?

Click to expand...

Again, I don't know Mori, but some of them fool you. A few turrets move the back coupling half instead of the front one, so the "lift" you would normally see is inside.

EmanuelGoldstein said:

Again, I don't know Mori, but some of them fool you. A few turrets move the back coupling half instead of the front one, so the "lift" you would normally see is inside.

Click to expand...

3pc Hirth


----------

Think SnowEh!
Ox

Getting some food for thought for sure. Thanks to all.

In response...

Yes the turret leaks around the big diameter. And yes I can manually recover the turret without any movement along X or Z.

Yes it gets stuck in one part of the program every time. This is the first program that this has happened in. I'm still leaning towards weight distribution. On a brand new machine it probably wouldn't matter. On a 20 year old machine??? It could be starting to act like an old car.

No there is no axial motion at all of the turret, but like EG said it could very well be inside the main housing.

The pages in the parts books are very crowded and complex. This being a live turret doesn't help along those lines either. I recall seeing what looked like a large pin or shaft. It could certainly be attached to that curvic or Hirth coupling I keep hearing about. I need to Google them and refresh my brain as to what they're all about.

By ladder manual I mean a print out. I have a Mori VMC with the ladder printed out. It has labeling and page cross references to help find your way around. Printed out or not, I'm still no expert on following ladders by any stretch. I know I can see the ladder in the control, but unless there is meaningful labeling I'll be no better then a deer in the headlights. I could run the tool change program I wrote and page through the ladder until I find movement in the highlighted areas. Would be a start. And I should be able to make sense of and inspect any Y or X adresses I come across. I can also reference them in the electrical manual.

Perhaps a lazy Sunday afternoon at the shop will get me closer to understanding.

Wondering what it would take to tear into the turret and fix the seals. I also notice quite a bit of corrosion and wetness inside the holes that are revealed after removing the live tool drive hole covers. Mostly it's a simple circular groove thingy keeping the live tool driven tabs aligned, but it doesn't look great in there. And at some point there is a shaft with seals and bearings exiting there and heading for the innards, which I bet don't like coolant at all. Though I am using Qualchem 251C, which when it dries back pretty much turns into something like pure oil.

Appreciate the ideas. Combined they could lead to a fix.

does it happen after the takeover? if so check your hydraulic pressure when the turret indexes and chucks cycle. maybe a weak pump or blowby on a clamping cylinder or combo of both

Ox said:

3pc Hirth

Click to expand...

Exactly Didn't want to go there tho, it's kind of a swamp.

I think some people have done the same with curvics but this brain she'sa kinda wore out.

I also notice quite a bit of corrosion and wetness ...

Click to expand...

Every time I've taken a turret apart it was nasty in there. If you've got the time to get in there, I'd bet a quarter you find the problem.

pcasanova said:

does it happen after the takeover? if so check your hydraulic pressure when the turret indexes and chucks cycle. maybe a weak pump or blowby on a clamping cylinder or combo of both

Click to expand...

Don't understand "takeover" Funny but I did add about a quart or two of oil to the hydraulic tank the other day. Jut happened to glance at the gauge and noticed it was down. The range of the sight glass is pretty small, but it was low. Wonder if I do have a small leak somewhere. I had the 2nd spindle hydraulic actuator off awhile back. Could be I left a leak there. Yet during turret movement the gauge at the pump is right on the mark and stays there. I will admit that the hydraulic system crossed my mind in all this.

EmanuelGoldstein said:

Every time I've taken a turret apart it was nasty in there. If you've got the time to get in there, I'd bet a quarter you find the problem.

Click to expand...

I've been thinking about my leaking turret and I think leaking is normal. At some point the coolant stream has to pass from stationary to rotary, so there is going to be a seal arrangement of some kind there. Complicated or not I don't know. But the machine builders had to realize that the time between coolant pump shutoff and next tool turret rotation was going to happen long before both coolant pressure and volume left the system. Meaning blow-by was expected. Just like at a HP coolant rotary coupling on a mill which might use a splash shield and drain setup. So I'm thinking the splash area inside the turret is mostly of little or no consequence. Although what they use to contain the splash may have wear elements that loose their effectiveness over time. And unfiltered coolant could certainly make a mess over twenty years. I can also easily imagine a stray chip making it's way into one of the teeth of this Hirth coupling and causing a problem.

Ox said:

I would ass_u_me that you have either a 2pc or 3pc Hirth type coupling.

Click to expand...

Speaking of Hirth couplings. I looked it up and am happy with what I see. This is a simply crafted, solid and potentially accurate indexing and clamping joint which should easily have along life. Especially when indexed by a servo system that can keep the alignment to within a fraction. I hear they can suffer fretting but little else. Now that I know what to look for in the drawing I may be able to spot what should be a very recognizable shape.

I wake up to find my lazy Sunday n the shop is being hampered by what is likely going to be 8-9" of snow. Hail Minnesota! Other then a good manufacturing base, why do live here?

Dave

To be clear, the program that youare running stops at the same point EVERY TIME?
And no other spots?

And to date - this has never happened before?


I think I would go on to the next job and see how it acts there before I $pent much time on this.

It's possible that you got a slight glitch in your program that you can't see that is buggering up the system.
I Shirely have re-written a full line of code and deleted the old one to git it to run right.


Is your library full?
I have had much trouble with my 18i messing up code if the library gets very full.

I have had my older 18 give me fits on indexing the turret to wrong positions when the control get;s too warm.

There may not be anything wrong with your turret.



Edit:

I am quite sure that balance would not play a roll.



---------------------

Think Snow Eh!
Ox

Ox said:

To be clear, the program that you are running stops at the same point EVERY TIME?
And no other spots?

Click to expand...

Si.

Ox said:

And to date - this has never happened before?

Click to expand...

Si.

Ox said:

I think I would go on to the next job and see how it acts there before I $pent much time on this.

Click to expand...

Gonna do just that.

Ox said:

It's possible that you got a slight glitch in your program that you can't see that is buggering up the system.
I Shirely have re-written a full line of code and deleted the old one to git it to run right.

Is your library full?
I have had much trouble with my 18i messing up code if the library gets very full.

I have had my older 18 give me fits on indexing the turret to wrong positions when the control get;s too warm.

Click to expand...

Oddly enough I filled the control beyond capacity for the first time during this job. Sort of suprised me really. Although it is a Fanuc which should not make it so surprising. I deleted a bunch of programs and reloaded. This work I'm doing is 10 copy and paste variations on a single program. All the same tools in the same sequence, just changing bore sizes and drill depths. But each one is deleted and the new loaded. Could be what you're talking about but...

Ox said:

There may not be anything wrong with your turret.

Edit:

I am quite sure that balance would not play a roll.

Click to expand...

Si and Si.

Dave C. :-)

13engines said:

Don't understand "takeover" Funny but I did add about a quart or two of oil to the hydraulic tank the other day. Jut happened to glance at the gauge and noticed it was down. The range of the sight glass is pretty small, but it was low. Wonder if I do have a small leak somewhere. I had the 2nd spindle hydraulic actuator off awhile back. Could be I left a leak there. Yet during turret movement the gauge at the pump is right on the mark and stays there. I will admit that the hydraulic system crossed my mind in all this.

Dave

Click to expand...

Takeover when the sub come in and clamps the part. Try your turret cycle program you wrote and add chuck open and close for both main and sub. Try that and see where your main hyd pressure goes.