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

Hi Fred,

Yes, you're right. I see that now. Finishing the radius should be
AFTER milling from the bottom. Then (as I thought I saw it), there is
only a thin web to finish the radius on (and do from either side).

I've also heard of casting (filling) part voids solid with something
like rose metal, or other low temp metal alloy, to give strength to the
part long enough to machine.

This would be a good "school" or "study" part project!

Alan KM6VV


imserv1 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