Re: Newbie: Machining an oval?

--- In CAD_CAM_EDM_DRO@yahoogroups.com, "gglines1" <gglines@c...>
wrote:

> Thanks Bill! I was hoping to find an easy way to program it
> directly in G-code, but it sounds like CAD will be the only way.
>
> George

I find doing it in a spreadsheet to be the easiest way.
since an ellipse can be defined mathematically it is a rather simple
matter to get a spreadsheet to define all the points and pump out G-
code.

let me know if you want to work out a program. since all you need to
define is the 2 main points plus the lenght for the 3rd point, we
could put it together and post it in the files section.

Dave

>
> --- In CAD_CAM_EDM_DRO@yahoogroups.com, ccq@x wrote:
> > Actually, a standard oval is generated from a diamond shape. to
> do it by hand,
> > (use the same method for cad) Use a 60 degree triangle to make
> your diamond
> > shape. In CAD, you can use copy-rotate on a line. Assuming the
> longest part is
> > oriented vertically, draw a pair of lines from the intersection

on

> the left, to
> > the center points of the two lines on the right, and vice versa.
> From the point
> > where these lines cross in the upper half, draw an upwards going
> arc through the
> > center points of the upper side lines of the diamond, and a
> downwards going arc
> > in the bottom half. Then from the two side points draw an arc
> through the
> > centerpoints of the opposite sides of the diamond. Erase/delete
> the diamond and
> > intersecting lines, and you have a classic oval.
> >
> > Bill
> >
> >
> > On Sat May 17 07:24:37 2003 turbulatordude wrote:
> >
> > >Hi George,
> > >
> > >unfortunatly, no.
> > >
> > >I did a CAD layout on an elipse broke it into quarters and then
> laid
> > >3 circles over one quarter. I was very happy to find that the
> offset
> > >from an arc to the elipse was withing a few thou, much better
> than my
> > >requirements for that project.
> > >
> > >For an elipse, you need to break up the curves into point to
> point
> > >steps. the more steps the closer to a perfect ellipse you will
> get.
> > >but for most software , each step will be a ramp up, and down

and

> > >stop. to the milling will be very slow.
> > >
> > >Back to an oval. An oval is 2 circles and 2 lines connecting.
> just
> > >determine your circle center points and cut one half circle, one
> > >straight, the other have circle and the remaining straight.
> > >
> > >seems like a very few lines of code.
> > >
> > >Dave
> > >
> > >
> >