Hello Guest it is October 25, 2021, 09:18:35 PM

Author Topic: Advanced Spindle Control  (Read 6598 times)

0 Members and 1 Guest are viewing this topic.

Offline Monty

*
  •  116 116
    • View Profile
Advanced Spindle Control
« on: January 29, 2010, 05:56:35 PM »
OK here is the issue.

I would really like to be able to have spindle positioning on my lathe. The problem is the spindle drive needs an add on card to do that and they are basically not available anymore.

It will however take a +/-10V analog signal for direction and speed.

Is there some type of card to convert step and direction to analog 10V that would allow me to put an encoder on the spindle and drive it like another axis? If so would this still work in typical turn applications. How would you get around the spindle sensing issues for threading?

Monty

Offline Hood

*
  •  25,838 25,838
  • Carnoustie, Scotland
    • View Profile
Re: Advanced Spindle Control
« Reply #1 on: January 29, 2010, 06:34:57 PM »
There used to be a board called the pixie that did that but its no longer made. I have heard Rutex do one but have not heard of anyone using one.
You would have to use SwapAxis() to change between spindle and axis depending on what you were wanting to do, ie positioning, rigid tapping etc you would swap spindle to A via macro, normal turning and threading you would swap back again.
Hood

Offline Monty

*
  •  116 116
    • View Profile
Re: Advanced Spindle Control
« Reply #2 on: January 29, 2010, 06:41:33 PM »
Hood,

So I would still need the 1 per rev signal for standard lathe operations? The encoder would only be useful for rigid taping etc. after swapping the axis.

First I've got to get the rest of the ghosts out of the machine.

Do you know a good Exorcist specializing in electronics?  ;D

Monty

Offline Hood

*
  •  25,838 25,838
  • Carnoustie, Scotland
    • View Profile
Re: Advanced Spindle Control
« Reply #3 on: January 29, 2010, 06:47:08 PM »
I was presuming when you mentioned encoder that your motor is a servo and the  drive can close the loop to your motor, is that correct?

Hood

Offline Monty

*
  •  116 116
    • View Profile
Re: Advanced Spindle Control
« Reply #4 on: January 29, 2010, 07:03:23 PM »
Yes,

It has an encoder. The positioning was done with an add on board. It could position either the motor or the load. depending on where you put the encoder. But I can't use any of that functionality because I can't get the board and even if I could it would be a real pain to interface.

What I had in mind was to move the PID loop to the +/-10V controller. So it would read the encoder on the spindle and move the motor to the commanded position. My drive would be a "dumb" amp at that point. The analog controller would receive speed and direction instructions from Mach. Rather inelegant I admit, but the only way I can get here from there without a new spindle drive.

Monty
Re: Advanced Spindle Control
« Reply #5 on: January 29, 2010, 07:19:26 PM »
I believe this is what you need:  http://pico-systems.com/spindac.html

Regards,
Ray L.
Regards,
Ray L.

Offline Monty

*
  •  116 116
    • View Profile
Re: Advanced Spindle Control
« Reply #6 on: January 30, 2010, 12:28:32 PM »
Ray,

That would work great if mach handled PID loops within the computer. It would work with EMC. But to work with mach I've got to have something with encoder input to handle the PID loop.

It may not exist.

Oh well, I might just have to start on the 5 axis machine.

Monty

Offline Hood

*
  •  25,838 25,838
  • Carnoustie, Scotland
    • View Profile
Re: Advanced Spindle Control
« Reply #7 on: January 30, 2010, 01:02:01 PM »
As said Rutex do one so might be worth giving them an email. There are other options but more expensive such as the Kflop/Kanalog and DSPMC and really too expensive for just a spindle.
What kind of servo/size? might be better looking for another drive.

Hood

Offline Monty

*
  •  116 116
    • View Profile
Re: Advanced Spindle Control
« Reply #8 on: January 30, 2010, 01:44:14 PM »
Hood,

It's a Yaskawa 5.5 KW.

I can do a lot of the things I want to accomplish using the 4th axis on the Bridgeport, but it makes a terrible mess and the additional setups are a pain. It would be great to be able to do it all in one shot in the lathe with all the mess contained. Plus I can use flood coolant.

I'm not really sure it's feasible without a brake on the main spindle. I'm not sure how well the motor can maintain position under load.

I'll contact Rutex

Thanks for lead.

Monty

Offline Hood

*
  •  25,838 25,838
  • Carnoustie, Scotland
    • View Profile
Re: Advanced Spindle Control
« Reply #9 on: January 30, 2010, 01:54:50 PM »
If the Rutex lead doesnt go anywhere maybe keep your eyes open on eBay, I have picked up a lot of servo drives on there and the most I think I have paid was £180 for a new 22KW one.
Hood