Centroid Community CNC Support Forum

So, managed to get a nice Bridgeport for not a lot of money. All electrics have been removed, have the original motors.

My thinking is to replace with 750W servos, something like DMM or similar.

My main question is about the spindle. The standard motor is only something like 1.5 or 2 HP and massive. The previous owner has taken the CVT mechanism out (not sure if it failed or not) and its now ready to run from a VFD and fixed belt ratio. Of course at slower speeds it wont have the torque it should have.

So, options. I've got a watercooled Chinese 4KW spindle, 24K RPM. I need to check the speed of the spindle (original) but could gear that down. Ive noted that there is a low / high gear ratio but not sure if the current setup allows me to use that, I got this all in boxes unassembled.

Alternately, Id consider a 1.5KW servo. Did this on my Denford Triac.

Can Acorn support a servo motor as a spindle (so basically 4th axis)? And if so, can I avail of any of the ability to rigid tap? How would I send this back in terms of encoder? I expect I cant do this but happy to be corrected.

Thanks

any servo drive that can accept 0-10 vdc speed command and has a direction CW/CCW (if needed) input (contact closure) and output quadrature encoder signal....can be used as a spindle motor.

cnckeith wrote: ↑Sun Dec 23, 2018 8:47 pm any servo drive that can accept 0-10 vdc speed command and has a direction CW/CCW (if needed) input (contact closure) and output quadrature encoder signal....can be used as a spindle motor.

Thank you, that is great news. Would I be able to do things like rigid tapping etc? Is the encoder input (like what I have on my lathe) then used for the accurate speed control?

I think I would run the original spindle motor for awhile.
Provided you can elt the encoder at 1:1 to the spindle, configure CNC12 correctly, you can rigid tap with Pro License

Marty

martyscncgarage wrote: ↑Mon Dec 24, 2018 6:37 am I think I would run the original spindle motor for awhile.
Provided you can elt the encoder at 1:1 to the spindle, configure CNC12 correctly, you can rigid tap with Pro License

Marty

Thanks Marty. I just realised that most servos probably wont allow a 0-10V input plus direction (at least I think not). I've also got a 4KW Chinese Watercooled spindle, might be worth trying to mount this. I need to confirm max speed of the MDI head. The speed plate shows up to around 3200-3800 rpm in red but many spec pages are showing around 4200 rpm as max. Clearly the more the better in most cases.

Chaz wrote: ↑Tue Dec 25, 2018 6:48 am

martyscncgarage wrote: ↑Mon Dec 24, 2018 6:37 am I think I would run the original spindle motor for awhile.
Provided you can elt the encoder at 1:1 to the spindle, configure CNC12 correctly, you can rigid tap with Pro License

Marty

Thanks Marty. I just realised that most servos probably wont allow a 0-10V input plus direction (at least I think not). I've also got a 4KW Chinese Watercooled spindle, might be worth trying to mount this. I need to confirm max speed of the MDI head. The speed plate shows up to around 3200-3800 rpm in red but many spec pages are showing around 4200 rpm as max. Clearly the more the better in most cases.

Why don't you post pictures of your new machine, including servo motors, servo drives, spindle motor and current spindle drive and the control cabinet....

Marty

martyscncgarage wrote: ↑Wed Dec 26, 2018 11:11 am

Chaz wrote: ↑Tue Dec 25, 2018 6:48 am

martyscncgarage wrote: ↑Mon Dec 24, 2018 6:37 am I think I would run the original spindle motor for awhile.
Provided you can elt the encoder at 1:1 to the spindle, configure CNC12 correctly, you can rigid tap with Pro License

Marty

Thanks Marty. I just realised that most servos probably wont allow a 0-10V input plus direction (at least I think not). I've also got a 4KW Chinese Watercooled spindle, might be worth trying to mount this. I need to confirm max speed of the MDI head. The speed plate shows up to around 3200-3800 rpm in red but many spec pages are showing around 4200 rpm as max. Clearly the more the better in most cases.

Why don't you post pictures of your new machine, including servo motors, servo drives, spindle motor and current spindle drive and the control cabinet....

Marty

I will do. I've got the original motors, been fitted with modern encoders (AMT 102). The rest is pretty standard, no electronics at all.

Chaz wrote: ↑Wed Dec 26, 2018 11:14 am

martyscncgarage wrote: ↑Wed Dec 26, 2018 11:11 am

Chaz wrote: ↑Tue Dec 25, 2018 6:48 am

Thanks Marty. I just realised that most servos probably wont allow a 0-10V input plus direction (at least I think not). I've also got a 4KW Chinese Watercooled spindle, might be worth trying to mount this. I need to confirm max speed of the MDI head. The speed plate shows up to around 3200-3800 rpm in red but many spec pages are showing around 4200 rpm as max. Clearly the more the better in most cases.

Why don't you post pictures of your new machine, including servo motors, servo drives, spindle motor and current spindle drive and the control cabinet....

Marty

I will do. I've got the original motors, been fitted with modern encoders (AMT 102). The rest is pretty standard, no electronics at all.

There is great interest in seeing the AMT Encoders run with All in One DC.....there isn't a reason it shouldn't work.....but I am waiting on AMT's larger format encoders due out the first quarter of 2019 to test them.

How did you fit the encoders to your motor shafts? The encoder stub must have been small enough to accomodate them? Did you take pictures of the install?

Marty

martyscncgarage wrote: ↑Wed Dec 26, 2018 11:50 am

Chaz wrote: ↑Wed Dec 26, 2018 11:14 am

martyscncgarage wrote: ↑Wed Dec 26, 2018 11:11 am

Why don't you post pictures of your new machine, including servo motors, servo drives, spindle motor and current spindle drive and the control cabinet....

Marty

I will do. I've got the original motors, been fitted with modern encoders (AMT 102). The rest is pretty standard, no electronics at all.

There is great interest in seeing the AMT Encoders run with All in One DC.....there isn't a reason it shouldn't work.....but I am waiting on AMT's larger format encoders due out the first quarter of 2019 to test them.

How did you fit the encoders to your motor shafts? The encoder stub must have been small enough to accomodate them? Did you take pictures of the install?

Marty

In my case Id like to use Centroid here, not All in One.

I bought them modded, ill take them apart and take some pics tomorrow.

All in One DC is a Centroid control designed with three DC servo brush servo amplifiers.