Re: [CAD_CAM_EDM_DRO] create a cut out vs pocket

In most CAM programs, you can program a rough pass to remove all of the
material in the pocket, and a semi-finish and/or finish pass which just
goes around the perimeter. If you only run the semi-finish or finish pass,
you will get an outline only and the middle will fall out in one piece..
The only thing you have to be careful of is that if you don't clamp down
the part that falls out (known as a "slug" or "drop") it can bind the tool
and break it when it cuts through. Another option is to set your dept of
cut to .003-.005" less than your actual material thickness, which will
leave the slug hanging by a thin burr, which you can easily break out with
your hand or a mallet, and clean up with a file or deburring tool.

On Mon, Dec 17, 2012 at 10:48 PM, Jon Elson <elson@...> wrote:

> **
>
>
> ebiz_59 wrote:
> > i have a part that is flat - say 0.25" thick and I want to cut a 1.75" x
> 1.5" double "D" shape out of the center of it. I can "pocket" it but that
> creates a whole bunch of chips that I don't really want or need to create.
> What do I call this cut out area instead of "pocket". The goal is to make a
> couple trips around the perimeter of the cut out area. THANKS!
> >
> Some people call this "trapanning". You make one (or multiple) passes
> just inside the
> final dimension, let the slug drop out, and then make a final pass to
> clean up the
> edges and bring it to final dimensions. I have some routines that do
> round holes
> and rectangular holes/slots, but these are specific purpose programs and
> don't
> handle arbitrary shapes like the double-D. Not knowing your CAD/CAM
> program, I don't know what they'd call it, but you can search for
> trepanning.
>
> Jon
>
>
>


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