Re: Digital screwcutting "gearbox"

--- In CAD_CAM_EDM_DRO@yahoogroups.com, "majorityuk2000" <john@h...>
wrote:

>
> Hi all,
>
> I am sure that thius question has been asked and answered many

times,

> so apologies in advance if it is tedious. However...
>
> I am interested in adding facilities to my Super 7 lathe to allow

it to

> cut threads using a stepper to drive the L/S, synchronised to the
> headstock through a phase-locked loop. A side benefit should be
> variable slow feeds and a "virtual saddle stop". I have worked out

a

> scheme to do this which I think will work but would like to see if

I

> can learn from others' experience first!
>
> Can anyone please point me to material on the web, or elsewhere,
> suggesting how this can be done, and/or other peoples' experiences

of

> doing it?
>
> Cheers,
>
> John Haine.
>

Hi John,
I'm also on this,I was thinking about the use of a microprocessor
like atmel 90s2313, and a 2x16 lcd.
FROG does make one for this purpose,but it does not have a lcd
display, instead it uses a series of "bips" and bops.
I was thinking of something a little more sofisticated.
Using the atmel chip and A3977 step driver from Allegro and a
little programming in bascom, I was able to have the motors moving
nice.
Still need to find a way to include a ramping in the software,
after that I'll think in how to sincronize the headstock and
steppers, I think this is not as dificult as implementing
acceleration for step motors.
if you want it off the shelf,do a search on the net for FROG CNC.

Fogassa.