Re: [CAD_CAM_EDM_DRO] Cutting an arc help G2/G3?

Hi George,

You haven't mentioned if you're using CAD or not. For CAD (could work
it out on a piece of graph paper), draw two 12" arcs from each end
corner of the 2.5" stock. These two arcs will intersect WAY off the
part. Then from the intersection point, draw a 12" arc. You should see
this arc intersect your two corner points.

Repeat this for the 11" arc on the other end of the stock. You now have
two arcs, two sides, and the locations of the arc centers. From this you
have the needed information to either program by hand (ouch!), or CAM.
You'll have to draw the tool path AROUND this part outline, of course
(unless you have G41/G42 tool comp). A little harder with out CAD/CAM.

HTH

Alan KM6VV
P.S. You wouldn't be making a FLYWHEEL by segments, would you? I may
be able to draw and/or create a toolpath for you (If Fred doesn't beat
me to it! ;>) )

P.P.S. Doing it on a Sherline? Visit SherlineCNC

gglines1 wrote:

>
> I have to cut a small workpiece with a curve. The workpiece will be
> 2.5 inches long, 1" wide and 1/2" thick. The long end of the
> rectangle needs to be cut in an arc to match a 12" circle, the
> shorter inside arc to match an 11" circle. Hard to describe, think
> of a 2.5" long piece cut out of a 12" ring that is 1" wide.
>
> Assuming I start with a workpiece that is a rectange 2.5" long by 1"
> wide, how would I program the arc cut? I can see programming a
> circle and letting the machine make a 12" revolution, but that would
> be really slow. I'm not sure how to program just the part of the arc
> that I need.
>
> Thanks,
>
> George