Using a centroid 4th axis for turning

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cncot
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Using a centroid 4th axis for turning

Post by cncot »

Gentlemen,
I. have a Centroid pro mill software on a 4 axis Bridgeport run with an Allin1.
Is there a way that I can use my centroid A axis to act as a lathe head, spinning without regard to position?
What is the maximum rated rpm of the centroid rotary head?
My torque requirements would be low, Likely turning small wooden objects...
If the rotary head cannot be "Position Ignored" Then how do I set it up to run for say, 20 minutes at max speed? Is there a limit to the rotary position counter? Do I have to stop and unwind periodically? How do I know if the "spring is wound too tight"?
See my report file in the previous post, Please
Thanks, Mike
cncsnw
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Re: Using a centroid 4th axis for turning

Post by cncsnw »

I do not know of any way to do that with the DC1 powering the A axis servo. As long as it is a servo-controlled axis in the Centroid system, it is only going to do interpolated positioning moves, coordinated with the positioning moves on all the other axes.

To do what you describe, you would really need to turn off the A axis in CNC12, and switch over the servo motor power connections to a variable- or fixed-voltage DC source, ideally switchable with a contactor so you can start and stop rotation with an M function.

While operating in this mode, the A axis encoder position could be displayed, but would not affect anything.

To answer your question, though, I think there are still some parts of the software that keep encoder positions in signed 32-bit integers, so it will wrap around (with perhaps undesirable effects) after a little more than two billion encoder counts. On your control, that would happen at about 1193 revolutions away from machine zero. If you are using it as a positioning A axis via the DC1 drive, then you need to re-zero the machine position periodically (e.g. with M26/A) to avoid reaching 1193 revolutions away from machine zero.
tblough
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Re: Using a centroid 4th axis for turning

Post by tblough »

Most servo motors have a 3000rpm limit. Most rotary tables have a 90:1 worm drive. That would mean the max rpm would be 33rpm.
Cheers,

Tom
Confidence is the feeling you have before you fully understand the situation.
I have CDO. It's like OCD, but the letters are where they should be.
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