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Author Topic: Sync mill spindle with rotary axis possible?  (Read 4519 times)

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Offline newatcnc

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Sync mill spindle with rotary axis possible?
« on: August 29, 2012, 03:48:23 PM »
Hi everyone
I am thinking of buying compucut gear hobbing sync hardware/software to allow me to cut helical gears on my mill.

However, I was wondering if it's possible to syc the mill spindle with a rotary axis using Mach for turning.

Anyone tried this?

I am a newbie and have used mach 3 for milling very successfully over the last year but I have no experience yet of cnc turning, that's another project.

Your guidance appreciated.

Nigel

Offline Hood

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Re: Sync mill spindle with rotary axis possible?
« Reply #1 on: August 29, 2012, 05:26:13 PM »
The only real sync you can do is with threading.
You can do a feed per rev but thats not really in sync.
What you could do however is if you have a servo (step/dir) or stepper as an A axis then you could sync it and any other axis just like you do with X, Y, Z etc.
Hood

Offline newatcnc

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Re: Sync mill spindle with rotary axis possible?
« Reply #2 on: August 29, 2012, 08:55:41 PM »
Hi Hood
Thanks for your reply.
To hob a gear using a helical hob (as used by commercial gear cutters) the Z axis will be fixed, the Y axis will provide depth of cut and the x axis feed, all independent of the rotation of the rotary or A axis.
Correct me if I am wrong, but I gather that Mach 3 will only accept 1 pulse per spindle rev when thread cutting.
So thinking about it a bit more, if you were to hob say a 10 tooth gear, for each rev of the spindle the rotary axis has to rotate 36 deg and in true sync with each fractional turn of the spindle.
I am beginning to think that the pulse rate per rev of the spindle has to be high for this to work reasonably accurately, which I don't think Mach can do.

So, I think your rely has helped me answer my own question and as you say, it won't give true accurate sync between the spindle speed and rotary axis. So no, mach would not be suitable.

The compucut system does actually have a very high pulse rate per spindle rev., so compucut it will have to be then.

Thanks again

Nigel

Offline Hood

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Re: Sync mill spindle with rotary axis possible?
« Reply #3 on: August 30, 2012, 03:00:29 AM »
Maybe I wasnt quite clear, if your spindle had a servo or stepper driving it then you could tell Mach it was an A Axis and it would be fully in sync with all other axis.
I use that occasionally for rigid tapping as my mills and lathes have servos on the spindle, I just do a swapAxis() in Mach and then code the spindle rotation as an A Axis.
Hood

Offline Tweakie.CNC

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Re: Sync mill spindle with rotary axis possible?
« Reply #4 on: August 30, 2012, 03:21:21 AM »
Hi Nigel,

If you haven't done so already you should perhaps check out Gearotic Motion http://www.gearotic.com/
Art and Bob have developed a pretty easy to use gear design software and method of use for helical as well a spur gears (active forum as well).

Just a thought.

Tweakie.
KEEP SAFE !

Offline newatcnc

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Re: Sync mill spindle with rotary axis possible?
« Reply #5 on: August 30, 2012, 06:46:40 AM »
Hi Hood
Ah, now I understand better what you were explaining. That's an interesting option, I could easily set the mill spindle up with a stepper motor. Thanks for that.

Hi Tweakie, yes I have the gearotic software, still playing around with it but it's great, I am definitely a fan of Art and Bob. These particular gears will be very small, probably 0.5 module so I thought hobbing would be best approach this time. I have plans for larger helical gears on another project for which I will use Gearotic to get g code and mill them with the rotary axis.

So much to learn

Thanks again

Nigel