Re:4th axis rotary with a 3 axis control

Darrell,

The clamping sounds good, close to what I was going to do (OK, a little
better!). Sounds like multiple "contours" aren't that important? I
don't have a lot of end-mills yet, but I guess if I go slow for the
"roughing" cuts, and finish up with another profile (tool path), it will
work. I don't think MAXNC does the tool comp, (G41/G42), so as long as
I'm doing multiple contours, I can easily put the comp. in there. Do
you suggest cutting the full depth (.625) for each cut, or do I need to
do multiple passes to get the depth down? Seems like a lot to cut
(roughing) on a Sherline!

Alan


Darrell wrote:

>
> ----- 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