Re: [CAD_CAM_EDM_DRO] Re: Technique for parting a part

Rob wrote:

> Milling..
>
> Take a super simple example..
>
> Billet - W4" D3" H1"
> Part - W3.5" D2.5" H.75" (just a rectangle - this isn't a real part,
> just an example).
>
> Would you machine away .25" of the height and then cut all the way
> down to remove the part? I worried that the part will get kicked
> into space after it cuts the very last remaining stock that is
> attached to the part.

If you were holding this in a vise, you might have to do as many as
6 separate setups to get it square and to dimension on all sides.
With some thinking ahead, you might be able to put parallels in the
right places so you could machine the top and 2 sides on the first
pass, and then flip it and machine the bottom and one other side.
This side would be square to the first 2 sides, and could be used as
a reference to machine the last side.

You don't generally "part off" a piece from the top. You generally hold
a piece bu the sides, in a vice, or clamp it to the table, and move
clamps as you work around the part. You would not usually clamp
around the perimiter of the stock, and then cut it away from the clamped
edges, leaving a 'ring' clamped in the machine when you are done.
The side forces produced by the milling cutter will very likely fling
the gouged part across the room if you try to do it this way.

If you want to mill all around a part, you may be able to clamp it at the
edges,
machine some features of the interior, and then apply clamps to the
interior features, remove the clamps at the edge, and mill the entire
perimiter in one pass. I have done this on some parts, after making
some special fixturing with holes in the right places.

Jon