Re: newbe CAD/CNC question - trying to get past 1st base!

The actual part is about 3"x3-1/2", aluminum. THe only critical
point is the location of the mounting screws. The remainder of
material removal is mostly for weight and nothing else. The radius
add marginal strength (can only guess) because that is on the side
that will have some stress (or maybe its just the way the part was
originally cut.

Ken

--- In CAD_CAM_EDM_DRO@y..., "imserv1" <imserv@v...> wrote:
> --- In CAD_CAM_EDM_DRO@y..., Alan Marconett KM6VV <KM6VV@a...>
wrote:
> > For the top, do the main, rectangular pocket first, and later on
do
> the
> > arc's from the side to finish.
> >
>
> If I was going to make just one, I would probably just drill
through
> where the radius is and then pocket down to where it starts from
the
> top, and then to inside so that the end mill stays away from the
> radius. I would not try to cut that radius all the way through
with
> the side of an end mill. Guaranteed to chatter. It will probably
> squeal real loud if you only try to go 1/2 way too.
>
> One problem with a "swiss cheese" kind of part like this, is that
as
> the metal is removed, usually the entire form will twist and warp,
> leaving things in the wrong places. It might be necessary to
leave
> some stock all around and then after all is roughed out, go back
and
> resquare/finish the length width and height, take skim finish cuts
on
> the milled surfaces that are critical, and THEN machine the
holes.
> This depends on what you need to do with the part.
>
> From the picture I have no idea as to the material or the size.
If
> it is a 12" cube, look out. If a 1 1/2" (most likely for only
$30)
> it might not be a problem in any event. Also the radii may not be
> critical and could be machined square.
>
> Best Regards,
>
> Fred Smith
> IMService