Tool Turret Index Failure

[hatchmar]

Hello again, We have been plagued with this problem for a long time now and maybe someone here has run into this alarm. We have several EMCO turn 320's (yea- old) and every single one of them at one time or another gets a "tool turret index failure" alarm. this is also sometimes along with a encoder fault. there are 2 of our machines that get this alarm quite often but there seems to be no one thing that triggers it. they may run just fine for weeks and then all of a sudden, every time it tries to index, we get the alarm. and then out of nowhere, it just stops throwing the alarms. our maintenance crew has worked on this over and over but nothing seems to do the trick. they have replaced the turrets, boards etc but it still does it. has anyone had this problem?

[ViperTX]

Not familiar with this machine...but when you index...is there a sensor that indicates to the system that the indexing has been accomplished? If this is a system that measures the current to indicate pass/fail of an index....then either the limits are drifting due to heat, age, or .......

[hatchmar]

yes there is a sensor (replaced), and it looks like what is happening is that the turret isnt locking in properly which the sensor sees and then alarms. we thought that by putting a new turret in, it would lock in properly because there arent any worn parts

[Gunner]

We had an EMCO turn 332 at my old shop. During the warranty we had a turret index alarm that sounds similar to what your describing. I'm sorry I can't help you with what they actually did to remedy the situation though. I know we had them come in for the problem twice. The second time they stayed for about a week and ended up replacing just about everything they could, including the turret. I left the company shortly after that and am not sure if they have had the problem again. I can call and ask if you'd like. I know since the fix, it hadn't been a problem prior to my leaving.

[HuFlungDung]

I don't know what is inside the turret, but I would be checking or replacing the turret encoder, and also checking the condition of any delicate coupling that might exist between the encoder and the turret spindle.

If the turret locks into position with a curvic coupling, of course, the encoder feedback needs to be properly phased in position so that the curvic coupling does not come down on top of itself. It could be that a very delicate adjustment of the encoder coupling is required to improve the turret positioning before clamping.

[DocHod]

check the turret encoder it may be just a little out of sync also if the turret is hydraulic driven it might be the solenoid valve,a bad coil or the wires to the coil actuating the solenoid giving you erratic problems hope this helps!

[trubleshtr]

Index errors and only 1 year old, and, on 2 machines....I would be going after warrenty, or at the very least turning the screws to the machine builder to fix the problem.

When you say you replaced the turret do you mean the whole assembly, motors and encoders and all?? Or just the turret head itself?

are you using any large heavy tooling?? If so, you may want to try and slow down the turret rotation or clamping,as it may have too much momentum/inertia when you are asking it to clamp again.
More thoughts...
does it always stop on the same tool?
has the machine ever been crashed.....I/ve seen alot of bent dowel pins on the clamping side of a turret that can cause mischieious behaviour.