Servo motor for spindle motor?

[jtroedel8487]

My mill(hurco hawk 5) is in dire need of a new spindle motor. I’ve seen some guys on YouTube building mills using larger (3.7kw and up) servos as motors for the spindles on their machines. Is this possible to do using my centroid acorn board? If so would the drive for the servo be used as the 4th axis drive in acorn? Would something like this require a modified plc? Just looking for someone to point me in the right direction...

[martyscncgarage]

Sigh....
I would put on a new 3 phase inverter duty motor and a good Sensorless Vector drive like the Automation Direct GS3 series.
I would gut the VS drive, belt the spindle to the motor at 1:1 and then put a timing belt pulley on the spindle.

The spindle servo drive you put on must be able to accept enable and reverse signals (Not require +/- 0-10VVDC to forward/reverse the drive), provide a differential encoder output and the motor and spindle need to be belted at 1:1 with a timing belt if you plan on rigid tapping. DMM has a combination that should work, though I had trouble getting the servo tuned correctly. Given the expense of the large servo drive and servo motor and machining adapters, vs. the cost of a new 3 phase motor and SVC VFD, I'd look hard at the latter.

My guess is you are looking for an easy way to rigid tap without actually fitting an encoder?

Just my .02
Marty

[tblough]

Sigh....

LOL

[jtroedel8487]

There’s a couple reasons I thought a large servo would be a good fit. 1. Servos have a very broad torque curve allowing you to run the spindle very low rpms with high torque. 2. The ability to orient the spindle for probes etc... 3. Holding torque at 0 rpm, Eliminating the need for mechanical braking.

[tblough]

You might want to use the search feature on the forum for others who have attempted this route. It normally doesn't go well - hence the sigh from Marty.

[jtroedel8487]

Lol thanks I’ll try that!

[martyscncgarage]

There’s a couple reasons I thought a large servo would be a good fit. 1. Servos have a very broad torque curve allowing you to run the spindle very low rpms with high torque. 2. The ability to orient the spindle for probes etc... 3. Holding torque at 0 rpm, Eliminating the need for mechanical braking.

1. Yes pretty flat torque curve.
2. Required both positional control as well as motor control. Why do you need to orient a probe? Stick it in the spindle and turn it.
3. Mechanical braking for what? Slow/stop the spindle?
VFD and braking resistor can do that.

How many Machining centers do you know that have a giant servo for a spindle motor? Most VFDs orient the spindle and provide encoder feedback.

Look forward to seeing how you make out...