Erickson Quick Change

I am getting a Bridgeport V2XT CNC with an Erickson quick change spindle. The machine does not have a spindle motor on it currently. I'm considering using a 1.5kw servo. How easy is it to drop the power to the spindle servo for tool changing? I don't want to rely on the servo to hold the spindle while I undo the quick change nut because if it comes out of position, it could violently whip back while I had the wrench engaged. I also need the power to drop out so I can indicate round parts.

It's probably pretty easy, but to be certain I/we/you need to review the spindle drive document(s) and see what features it has.

Likely there will be an 'enable' input to your drive.  This could be connected in your configuration to a physical or screen/GUI button to 'lock' or 'unlock' the spindle motor.

Have you considered using an induction motor and VFD instead of an AC servo?  Unless you need tight angular positioning for some reason, a standard induction motor + VFD + spindle encoder can do a very nice job on a mill - including rigid tapping.  And no issues free-wheeling the spindle during tool changes or indicating a part...

Looks like your BP came with a 2hp 3-phase induction motor.  Some mounted on top of the head, some were underslung - those look non-standard.  If you've got a top-mount model, it's likely a standard NEMA frame; a used motor could bolt right up without fussing with an adapter to a 130mm or 150mm servo flange.

That's the problem, the motor is underslung and standard frame motors are too long. It's also missing the variable speed drive components that were on the motor end. To buy a used motor and drive pieces would be $2,000.00.- $2,500.00.

BGM1956 wrote:

That's the problem, the motor is underslung and standard frame motors are too long. It's also missing the variable speed drive components that were on the motor end. To buy a used motor and drive pieces would be $2,000.00.- $2,500.00.
 

As soon as I saw pics of the two variations online, I crossed my fingers for you...

In that case, I think one of those short 180mm frame Kawasaki or Yaskawa servos would be perfect.

Like this:
hgrinc.com/productDetail/Motors/Used-Yas...o-Motor/06230990046/

Some older Yaskawa drives (Sigma 3?) can do step & direction inputs and take incremental encoders.  Newish ones have (I think) proprietary encoder outputs, so you'd be stuck with a matching Yak drive.

Either way, all those drives have 'enable' inputs.  It'd be pretty simple to cook up a button to disable the drive.  It'd also be possible have an M5 command also trigger a delayed drive disable so it always turns off - freewheeling like the original spindle unless an M3 or M4 were active.

And while you're figuring out the drive system, I'd recommend a poly-v belt rather than a timing belt: your ears will thank you.  You'd need to put an encoder on the spindle directly (or timing belt driven at 1:1) for rigid tapping as there may be a slight amount of belt slip with the poly-v.