RE: [CAD_CAM_EDM_DRO] cnc gear hobbing on a horizontal mill *info needed*

I had a play with this idea and got it running with about 3 lines of code in
turbocnc, a 1 pulse per rev sensor and a rotary axis....
PK

> -----Original Message-----
> From: CAD_CAM_EDM_DRO@yahoogroups.com
> [mailto:CAD_CAM_EDM_DRO@yahoogroups.com] On Behalf Of Lester Caine
> Sent: Friday, 26 May 2006 2:52 PM
> To: CAD_CAM_EDM_DRO@yahoogroups.com
> Subject: Re: [CAD_CAM_EDM_DRO] cnc gear hobbing on a
> horizontal mill *info needed*
>
> ask wrote:
>
> > I found a little post made by john stevenson on hooking a
> encoder to
> > the mill spindle then using some kinda divide by chip to make a
> > stepper move the dividing head in time with the spindle.
> does any one
> > now were I can find more info on this set up.
>
> The article was in MEW entitled Gear Hobbing Without Change Gears.
> Brian Thompson wrote it with some input from John :)
>
> It uses an encoder on the spindle which was hand cut to give
> 1000 pulses per rev, and uses the edges from that encoder
> feed to provide 8000 pulses per rev to the divide circuit,
> which then runs the stepper motor (200 pulses per rev) at a
> ratio of the spindle. The output of the stepper motor motor
> goes through a 20 to 1 worm drive, so that the final system
> has an accuracy of 1/2 a rev per spindle revolution.
>
> ( I'm still trying to work HOW you use it to cut the gears ;)
> , but the logic makes sense )
>
> I have a glass 2000 lpr disk and matching sensor ready to
> load up on the spindle (under £40), but I've not had time to
> do anything with it. Since the worm ratio on my rotary able
> is 90 to 1, I either need more pulses, or a different rotary table :)
>
> --
> Lester Caine - G8HFL
> -----------------------------
> L.S.Caine Electronic Services - http://home.lsces.co.uk Model
> Engineers Digital Workshop -
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