Re: Cutting an arc help G2/G3?

Alan,

Thanks. I'm programming directly in G codes. I have Dolphin
CAD/CAM but don't have a post-processor yet that will work with my
mill controller.

George

--- In CAD_CAM_EDM_DRO@yahoogroups.com, Alan Marconett KM6VV
<KM6VV@a...> wrote:

> 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