Re: [CAD_CAM_EDM_DRO] 4th axis rotary with a 3 axis control (and other tricks)

----- Original Message -----
From: "Alan Marconett KM6VV" <KM6VV@...>
To: <CAD_CAM_EDM_DRO@egroups.com>
Sent: Tuesday, September 05, 2000 12:51 PM
Subject: Re: [CAD_CAM_EDM_DRO] 4th axis rotary with a 3 axis control (and
other tricks)
>
> OK, now I have a real simple *NEWBE* question, I've got the part
> designed, and I can generate a "tool path" around the part's outline,
> but it occurred to me, this part is .625 thick, and nowhere square (it's
> an eccentric follower, 1" dia on the bottom, .63" dia on top of a "pear"
> shaped part, 1.69 overall). The part has a .75" bore through on the
> bottom end, and two ears with a .25" bore through them at the top, both
> top and bottom bores parallel (.JPG on request).
>
> HOW do I hog it out of a 1" x 2" x 1" thick piece of brass? I
> understand how to do a pocket with an island (which this is not), but
> how do I plan the cuts to remove all the outside? I really don't want
> to just plunge down and cut the outline of the part out directly on the
> Sherline. I thought about cutting around the part as if it were an
> island in the raw stock's outline, but that didn't quite work out with
> the pocketing command, that I could see.

Not having seen the part, I would clamp the raw stock in a vise and drill
the holes. Then I would face the block off to the required thickness. Then
I would drill a couple of holes in a block of steel at the same positions as
in the part to make a mounting fixture, tap them to take bolts and mount
the stock on the block clamped in the vise. (make the block small enough
that the part hangs over on all sides) If you have G41/G42 cutter comp,
tell the control that your tool is larger than it really is and the machine
will
cut a roughing pass. Reduce the tool size untill you are using the actual
tool
size for the final cut. If you dont have G41/G42, you will have to draw each
tool path.
Darrell

>
> I'd rather it was cut as series of "bigger" outlines, that gradually
> worked their way into the brass block (easy intrusions into the edge of
> the block). Do I have to just plan a set of bigger and bigger outlines
> (tool paths), and slowly work my way down? Is there a standard function
> to do this? I studied Vector's pocketing command, what would you call
> this? It would be tough to cut the outline by hand on the mill, I've
> probably only cut straight lines manually up till now!
>
> Thanks again,
>
> Alan
>
> ballendo@... wrote:
> > .......cut
> > If we set up a rotary table (commercial,sherline,emco,msc,etc.)with a
> > stepper motor. Or just use a strong stepper by itself!(prob'ly need
> > some gearing or belt/pulleys if the work is of any diameter at all.)
> >
> > Mounted at right angles to the mill table (axis of work aligned with
> > the X axis, makes it an A(technically, but we're gonna do a work
> > around).
> >
> > Say we want to put a part number(or engrave a picture) on a cylinder
> > mounted as described above. We only have three axes to work with.
> >
> > Plug the (4th axis) rotary described above into the "Y" axis driver.
> > Now the rotary gets the "Y" steps, X and Z work as always.The trick,
> > and its not really a big one, is to set the "Y" steps so that the
> > rotary (tangential)distance has the same effect as the linear
> > distance Y had before. Then this will work with any program
> > previously written for XY on this machine!
> >.......cut
>
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