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08-30-2007, 05:51 PM #1
Man o man some days you just wanna walk out the back door and say "screw this....I've had enough!" One thing after another this week,I swear! Running a 1500 pc job on my Ikegai lathe and every now and then the turret gets hung up on top of one of the curvic ring teeth and can't clamp. Ok...at first I thought it to be just a random thing.....happened maybe a couple times a day. Have to shut the machine down, power it up and index the turret to another station to get it all back in working condition. Not today.....every stinking fifteen minutes it's getting hung up. Mostly between tool two and three, but now in other spots as well. Losing my shirt now on the job because of all the down time, and have resorted to putting the machine on hold and placing a pipe between two of the turret stations and giving it a quick pull to seat the turret, then pressing cycle start to resume the cycle. Why is this doing this? It is a ram type lathe, if it helps in diagnosing. I really need to run this all weekend to get these parts out and the interruptions are killing me! Any one have any ideas of what to do to remedy this? Why do these things always happen right before a long holiday weekend? Thanking you all in advance.
08-30-2007, 05:56 PM #2
Is it an electric turret? Like a Duplomatic?
Like this beauty.
08-30-2007, 06:23 PM #3
My first guess would be there's excessive play in the indexing drive. Somethings worn out or out of adjustment. unclamp the turret and wiggle it to check for play..........
.....or maybe this is SO obvious you've already done that??
08-30-2007, 06:45 PM #4
Check that the tools are well distributed weight wise then the next thing is to look at the resolver on the back end of the ram.Coolant works it way into them over the years and causes problems.According to NC Engineering,the UK agents that is the biggest source of problems on the older Ikegai`s.
08-31-2007, 05:42 AM #5
Is it sticking at the end of the indexing just before it locks into place. If it is in the back of the crossslide there is a knob with a scale around it on one of the solenoids. This controls the speed at which the turrent moves as it comes to lock into position while iondexing. Turn it down. This will slow the final part of the index down.
08-31-2007, 07:16 AM #6
hz253......it's not really sticking so to speak. It's just not lined up correctly so that when it clamps, it's clamping on top of the teeth instead of meshing with the teeth. It's almost always between tool 2 and 3, but it does happen at other stations, just with not as much frequency.
Mark....weight wise it is distributed.
What is the resolver? If I do open up the ram, I wouldn't even know what to look for, can you elaborate on that?
08-31-2007, 08:55 AM #7
Why I asked if the Turret was electric is because the Duplomatic is on my Romi. A previous owner had run a ground wire from the control cabinet directly to the turret. I have found that on occasion my turret does what you are describing. I has always turned out that the little ground wire was broken. Once it was reconnected the turret would go back to working the way it should.
This may not be your issue. I don't know how your turret works but if it is electric it would be worth a wild ass try. [img]smile.gif[/img]
08-31-2007, 09:23 AM #8
I had a monster hydraulically driven turret doing kinda the same thing, tore it down and it was broken return springs. If its missing long my guess is you have a mechanical issue affecting pullback timing.
08-31-2007, 09:59 AM #9
I have a Monarch Metalist that does this on occasion. Usually with unbalanced tool loading. A large urethane dead-blow hammer takes care of the problem. We got pretty good at tapping the turret with the hammer as it was indexing to help it get in position. Might get you thru the weekend.
08-31-2007, 05:08 PM #10
Russ,I had a look at my turret this afternoon.There is a large cover on the top of the ram at the furtherest away end from the turret.The resolver is under that I believe.Would be worth having a look.
I also remember having this problem on another machine where I fixed it by changing a parameter but that machine had a 6T the same as my Ikegai and I seem to remember yours is a 5T so I don`t know if it can be done that way.
Also I`m calling this a resolver because the agent calls it that but I`m more inclined to think it would be an absolute encoder.Do you have to reference the turret at power up or does it know where it is?
08-31-2007, 05:19 PM #11
is it a hydraulic driven index or a servo driven index? what tells it actual position? a series of digital switches or an actual encoder on the rotating turret? What unlocks the cervic? what pulls it back? My bet is that it is something mechanical...
08-31-2007, 05:51 PM #12
Mark.....it is a 6T. I do not have to reference the turret upon start up. The top of the ram has
two covers....one which takes up practically the entire length from the turret back to the indexing motor, then there is the oil filled housing then another cover which when opened is full of wires and terminals. Taking off the cover on the end of the ram reveals the index pulser. Everything in the compartment with the wires and the index pulser is bone dry. I have not taken off the long cover on top of the ram, only because there is gasket all along the entire mating surface and I do not have gasket material on hand. At the back of the ram there is also a Flow Control Valve which is currently set at "6" on a scale of 1-10. Turning it down made the indexing not work at all.....while turning it up a little did not appear to have much of a difference. What is happening is this......
If indexing from tool one to tool two. The turret while turning counterclockwise turns just beyond where it should stop and clamp and as it's clamping the teeth meshing causes it to turn back clockwise to seat in the curvic ring. But what happens sometimes is it clamps down on top of the teeth causing the machine to halt. It most often occurs between tool two and three, but it will randomly do it in other places as well.
1.)What does the Flow Control Valve do?
2.)Can this be fixed by parameters?
3.)Do I dare take off the large cover on the ram, and what would it help diagnos?
4.) The oil in the housing for the motor that indexes the turret at the back of the ram is very low on oil.....(bottom of sight glass....well below the red line) could this be part of the problem?
Thanking you in advance for all your help.
08-31-2007, 05:53 PM #13
Wille......it a hydraulic driven turret. Don't know the answer to the rest of your questions, but working on it.
08-31-2007, 06:27 PM #14
Russ,my machine has two hydraulic valves at the tail end of the ram.One is a double solenoid and the other is a single solenoid spring return.I think they control the index (I don`t have elec or hyd drwgs for this).
The single solenoid valve will unclamp the turret and the double one will operate the motor to index it if not it will be the other way around.With the control powered up and the hydraulics running,manually actuate the single sol valve and see if it unlocks the turret.If so,get someone to hold the solenoid in and try pushing/pulling on the turret to see if there is any play.This will decide whether it`s wear or a fault.
If there is no play,have a look in the box with all the wires and the "pulse coder and see if there is a limit switch in there.There may be two,one to tell the control the turret is locked/unlocked and one to tell the control it is on station.
You should be able to tell this from the elec drwgs if you have them.
If you have an on station limit switch I would suspect that.
I have hydraulic turrets on some lathes and the on station switch actually tells the control when to release the solenoid which is controlling the index motor.I have had problems with the operating cam being worn and the switch needing adjustment and also with the switch just failing to break/make occasionally.
I am working on site all weekend but if I am in the workshop over the weekend or Monday I will lift the cover of mine and have a look at the setup if you`re still stuck.
The flow control valve will set the index speed.Without looking I think the oil level you are seeing is lubrication as the oil for the motor should come from the hydraulic pump unit.
BTW if you have elec drwgs I wouldn`t mind buying copies from you.
08-31-2007, 06:49 PM #15
Hey Mark....appreciate the help. I am going to get some pictures on here to try and make this easier. I'm not sure if I have all the diagrams you are referring to, but if I do I will make some copies for you and either email them to you or ship them off. It's the least I can do for your time helping me out. Going for dinner now. Will get out there with my camera later on and take some pic's. Thanks again.
08-31-2007, 07:09 PM #16
My bet would be the absolute encoder.
08-31-2007, 07:27 PM #17
Wrustle, my Cincinnati had about 12 die springs that return the turret onto the cervic when clamping. Mine was doing the same overshoot intermittently. 9 of 12 springs were broken. Tear it down and replace the springs, i bet its your issue.
08-31-2007, 07:52 PM #18
Thanks Willi.....I'll check into that.
08-31-2007, 08:48 PM #19
We screwed with speed, switch settings, etc on mine for nearly 6 months, would seem to get better until you really needed it to run, then would come back. Get out your parts book and look at what returns the turret and how it comes apart. Once the valve closes it expects the turret back in X many milliseconds, if the springs are weak/ broke the turret comes back a few milliseconds too slow an you are on top of the tooth instead of in it, or worse, a tooth off on a small expensive boring tool.
08-31-2007, 11:11 PM #20
FWIW 2 of the Mazak Qt6s at my old place of employ did just this from time to time. it turned out to be coolant in the encoder housing. the gaskets get old and start to leak and the way covers aren't great at keeping the coolant from getting under them and running down the turret slide. The X axis servo happens to be mounted relatively low it wasn't unusual for the servo to be wet. take off the encoder cap dry it all out and it would work fine for another few months or so.