[RickPflimlin]

For the most part my 770 has been great. A few months ago it started making a clicking sound when the spindle stops. Everything else is just fine. Is this a spindle brake? A solenoid clicking on and off? The sound varies in intensity. The example below is medium. At time it's much louder, and it quit altogether for a month. It's back now and I would like to track it down.

[pickled]

That doesn't sound like anything that mine does. I'd check to see if the pulley retainer nut is tight. Also you might want to take a look at that lovely plastic fan and housing on the motor. If something managed to find its way in there it could make some noise. Every once in a while I get weird noises from the motor door not being fully seated in the hinge. I just put some high viscosity grease in the pin bores and it doesn't ride up on me any more. Good luck!

[RickPflimlin]

Thanks for the reply. At first I thought it may be spring loaded brushes, or some sort of spring loaded motor brake popping out when the motor slowed. To that end I replaced the motor, so that would also rule out the fan. While I had the motor out I felt the spindle and it seems fine. I'm sure it's not the motor door, but I am also sure the noise is coming from inside the motor housing. I'll check those retaining nuts.

[RickPflimlin]

Dang, everything seems tight. It would seen that only the spindle remains. That or some sort of relay switch clicking off and on. Does anyone know how the motor brake works?

[pickled]

You had a spare motor? Wow you just one-upped me on the "critical" spares list :-). So the noise is still there after the swap? Do you have anything plugged into the coolant outlet? It doesn't sound like a typical air solenoid, but hey I'm grasping at straws here. I believe that the motor braking is performed via the VFD phasing itself. I'd still try to see if you can see anything moving around somewhere at the stop. I'd mount a camera up top shooting down into the motor housing and film while you are shutting it down just to rule out some crazy movement before tearing into the rest of it. Along the same lines as this trouble shooting you could also bypass the safety door switch (kids don't try this at home :-) for an on-off cycle or two with the door removed. Just to see if you can spot anything else. Based on that video it sounds more like mechanical impact than a relay contact would to me.

[RickPflimlin]

I agree it sounds mechanical. Sometimes it's much worse than what I caught on the video. I need to learn how the VFD phasing works. I'm thinking the (maybe broken) signals being sent to the motor could cause the mechanical sound?

[rdsi]

My first thought was that thing was stopping pretty fast and maybe something was slipping. The fact that it seems to vary in intensity could be the amount of mass you have mounted on the spindle.

Anyway, the VFD uses a braking resistor to to dissipate the regenerative power from the motor when decelerating. There are a number of parameters within the VFD that controls how this accomplished. If the VFD detects any problems with its function it typically throws an error code and then lets the motor coast to a stop. Since your spindle is stopping pretty fast I don’t think this is the case.

If you want to know more about the VFD I talk about how to reprogram it here. There are links to the VFD manual & an application note about how to unlock the security feature if enabled.

Good Luck ...

[RickPflimlin]

Thanks Rdsi. I will do some research.

[CountrySmith]

I had a similar noise problem with my 770 as the spindle was coasting down. It was a spindle bearing. Tormach replaced the spindle cassette under warranty. That was four years ago and the problem hasn't recurred.

I have hopefully attached a zip folder with three recordings of the noise.

You might try pulling the belt. If you still have the noise, it isn't the spindle.

R J

[RickPflimlin]

I had a similar noise problem with my 770 as the spindle was coasting down. It was a spindle bearing. Tormach replaced the spindle cassette under warranty. That was four years ago and the problem hasn't recurred.

I have hopefully attached a zip folder with three recordings of the noise.

You might try pulling the belt. If you still have the noise, it isn't the spindle.

R J

Although my sound is different (more load clicks) your idea to pull the belt showed that the spindle was the problem. Mine is not under warranty so I'll need to save for a new one. Thanks for the idea and input.

[mactec54]

For the most part my 770 has been great. A few months ago it started making a clicking sound when the spindle stops. Everything else is just fine. Is this a spindle brake? A solenoid clicking on and off? The sound varies in intensity. The example below is medium. At time it's much louder, and it quit altogether for a month. It's back now and I would like to track it down.

The spindle bearings and cage are skidding, if you don't need the spindle to stop as quick as it is, just ( 1 ) parameter to change in the VFD which is the deceleration Parameter this will help, but most likely the Bearings are not suited for this type of spindle use

[SCzEngrgGroup]

Although my sound is different (more load clicks) your idea to pull the belt showed that the spindle was the problem. Mine is not under warranty so I'll need to save for a new one. Thanks for the idea and input.

No need for a whole new spindle - Just replace the bearings. It's a pretty simple job.

Regards,
Ray L.

[CountrySmith]

Tormach advises against repairing the 770 spindle assembly, stating the spindle cartridge must be replaced as a unit, due to balance of the spindle for 10K operation. (sect. 9.7, bullet 6 in the old manual, sect. 9.4 in the new manual) That said, the new manual lists part numbers for all the components.

If my spindle should go out when out of warranty, I would attempt a repair as well. The rationale being that nothing would be lost aside from the bearing cost and some time if the the rebuild didn't work.

When I replaced my spindle cartridge, I made witness marks on all the parts before disassembly so they could be reinstalled to the same position. The replacement cartridge arrived with a loose preload nut so I had to make that adjustment.

I made my own spanner wrenches for the preload nut and the pulley nut. The pulley nut spanner was made by modifying one of the extra 22mm open end wrenches that I got with the TTS kit. Since the preload nut is recessed, I made a socket for it so I could adjust the preload in situ. Following is a shot of the SolidWorks model and drawing for the preload nut wrench.
Attachment 336964

[SCzEngrgGroup]

Tormach advises against repairing the 770 spindle assembly, stating the spindle cartridge must be replaced as a unit, due to balance of the spindle for 10K operation. (sect. 9.7, bullet 6 in the old manual, sect. 9.4 in the new manual)

If all the parts are kept in their original orientations (and I suspect that means just putting the pulley back on the spindle shaft in the same rotational position), there is no reason balance would be affected in the slightest. Even if not, finding a shop to re-balance it should be easy and inexpensive, compared to the cost of a complete new spindle cartridge.

Regards,
Ray L.

[RickPflimlin]

Tormach advises against repairing the 770 spindle assembly, stating the spindle cartridge must be replaced as a unit, due to balance of the spindle for 10K operation. (sect. 9.7, bullet 6 in the old manual, sect. 9.4 in the new manual) That said, the new manual lists part numbers for all the components.

Parts are listed but they are not for sale?

[SCzEngrgGroup]

Any decent bearing supply house should be able to sell you everything you need. Just take the originals in with you, or write down the part numbers, which will be engraved on the originals.

Regards,
Ray L.