Spindle slows to a stop for no reason.

Today for some unknown reason my QT-8 while running in auto mode decides to slow to a stop, not like its commanded to stop but free wheeling to a stop. There are no alarms on the operators panel or on the spindle drive.

The only thing I'm finding is the start light (for MDI) is flashing. If I push home then back to auto it starts back up no problem. It does it with no particular frequency, just when it feels like it. Any Ideas?

T32-B control.

Spindle!

Hello,

Bumber! I have a 94 QT 8 and a couple of QT 20s all with M+ controls, never seen that before. Had a QT 15 with T32b, none there either.
Are you taking a heavy cut? I was thinking belts at first but the M.D.I. thing, that might mean having Mitsubishi reload some fresh software for you.
On a T32 I think there is an L.E.D. on the spindle drive, see if you can catch something there.
What kind of shape is your incomming power?
Hopefully someone else has better news for you!

Good luck!

LandM-1

Spindle slows to a stop for no reason

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Oh there is a reason, you just don't know what it is yet, and don't know how much it's going to cost.

I had that happen a few times running on phase converters, but that was the whole machine shutting down before I slowed up the acceleration on the spindle drive.

Did it happen during a rapid? Spindle ramping up? Heavy cut?

I'd start with the power.

The job I'm running right now is 1.5" 6061 with light cuts. It seems to happen most while its cutting along the Z .075" DOC steady RPM. It hasn't happened during rapid or tool changes. I am running a 20HP phase converter for the past couple of years and have slowed the accel/decel in the parameters. While the Mazak was giving me fits, the Hurco VM-10 was singing along just fine which seems to be really power sensitive.

I had to leave early today to head out on a trip so I'll have to wait to do any trouble shooting.

I have seen the QT-8 you have for sale, if you were on the east coast I would snatch that up in a minute. I lay over in LAX often and thought about driving up to have a look see, just the thought of shipping cost keeps me away. The 8 is the perfect size for what I do and would love another, just not a B control.

dave i would say once your mazatrol savy any of the other controls would be in your skill set or learned with no problem
have you checked for alarms on drive?

I've got a "B" now and hope the next one will be a T+ or better. The B works fine for what I'm currently doing and have become pretty decent a getting it to do what I need but its still a strip down control.

I didn't have time to really do any trouble shooting, had to finish the job I had running, hit the shower and drive like hell to get to the airport and still signed in 15 late for my trip.

I have downloaded the FR-SE (I think that is correct for my machine) guide off the MEAU site and have read up on it in hopes to be ready to do some trouble shooting when I get back. It shows the location and function of each LED so I'll have more to report soon if one of them is on when this happens again. Someone mentioned in an earlier post that the software may need to be reloaded, Is the software located on one of the 2 E-proms or did they mean the parameters may need to be reloaded?

Thought that someone my have had this happen before and it might be a simple fix. Have 400 pieces of 6" 6061 cut and waiting to be machined and hoped to get a leg up on this problem before I return.

Dave, since your QT8 has a T32 control, I would say you have an FR-SF spindle drive, not the older FR-SE.

The led's on the drive should indicate the source of the coast-down. If not, then it could be a "phantom" problem that could be tough to diagnose. At least until the drive croaks completely.

It might be an overheat condition on your drive, which could be caused by one of the two spindle drive fans locking up. They are mounted on the top of the drive, and protrude out the back. MEAU's manual shows 'em, and how to remove/check/replace them.

Don't hesitate to call MEAU in Chicago. If you get the right guy (you may have to ask to speak with someone else), they can be very helpful.

Good luck,

Greg

Usually when this happens it means you have lost signal with the encoder.

Ran her 10hrs hard today without any problems with the spindle stopping. In the past I have run into other glitches from coping existing programs and editing them instead of starting from scratch. I'm hoping this was another one of them. Greg was correct that it does have an FR-SF spindle drive, not the older FR-SE.