We have a QT-250 that periodically strips the gear from the servo motor that
turret. The gear is milled into the shaft and turns a pricey 3 piece curvic
that has the
other part of the gear train cut into it.
Needless to say, the pieces from gear A travel around gear B and makes a 5000
This has happened > 4 times in the years I've worked where I work.
Anyone have similar issues with Quick Turns? Resolution?
On Thu, 12 Feb 2009 17:36:03 -0500, firstname.lastname@example.org wrote:
I have rebuilt 3-4 250's with and without live tooling in the last 8
Sounds like this one has no live tooling and has a hydraulic motor for
All of the live tooling machines have a belt drive to the shaft that
indexes the tooling
No matter it has to be mis-aligned or starts before the turret is
If you need any help you can always call me@714-334-4261 I work on
Mazaks a few days every week.
I've been to Florence once for training. I saw some big mills with Eagle Picher
machining base castings. I didn't work at the machining side of EP but I once
EP for a couple decades. I got a smile seeing that American Iron was helping to
PS sorry about misspelling problems in header. Damn spell check doesn't check
I don't know the 250 specifically; but I have a couple QT's that
routinely eat up a lot of my repair time. It sounds like the index
motor is starting before the turret is fully unclamped. The couplings
are still holding the turret while the gears are trying in vain to
rotate it. Or maybe it's trying to clamp before the motor is finished
positioning. Either of those should give some visible or audible clues
if you watch the machine carefully.
Unclamp confirmation before indexing is just a prox switch, which
may be out of adjustment, or may even be caked with chips and crud, and
giving intermittent too-early indication that it's safe to index. Clean
and adjust the prox in that case, or maybe replace it. If the clamping
starts too early, before the motor's done its job, that might be an "in
position width" setting on the servo that's not fussy enough. Check the
details and parameters of that particular drive. Wear and backlash can
make it necessary to have the servo wait a bit after cycling, before it
tells the PLC that it's happy with where it's at, and allows clamping to
Mazak uses big bushings on most of its machines, rather than
bearings, to support the turret shaft when its unclamped. If these get
worn, there might just be too much resistance to rotation, which can
also kill the gears. Unclamp the turret (or catch the machine just
right in mid-index with the E-stop button), and see if you can rotate
the turret easily by hand. If not, then maybe the gears can't turn it
either. Be sure you know how to recover from an interrupted index
before trying this, or you'll hate me in the morning.
This machine was here before I was. Another tech called Mazak and they said our
parameters in the MRJ2 controller were not correct as in full speed a head, full
The machine was purchased in 97 or so and I wasn't there. Looking at files
techs saved the parameters to disk doesn't come up with a parameter set that is
different than what we have.
It may turn out that at some point in time the MRJ2 indexer was replaced and
settings were used. Maybe the hdd failed, who knows, no institutional memory.
I did check for an early unclamp signal.
I'd love to see a parameter file for the controller from a QT-250. One night
tech got a smart guy, the next time a script reader. Tech support is a very
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