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

I'd do it somewhat different based on years of experience in industry....but
I'd say the part is relatively simple

First, I'd use a clamping fixture that would allow the use of the same
origin point for all operations.

"Pre-machine one surface to obtain a flat locating surface.

1. Clamp the part finished side down in the fixture, finish the opposite
surface (will be on top), one side, & one end.
2. Turn the part 180 degrees, finish the other side & end.

The block is now square.

1. Set the block on end and drill and ream the three holes
2. Turn the block on one side & drill and ream the single hole
3 Turn the block bottom side up & mill the three slots
4. Turn the part over, drill and tap the 6 screw holes
5. Mill the thru slot using a combination of square and ball nose or bull
end mills

Actual cutter selection would be based on the size of the part. I'd use
the largest size possible to reduce machining time.

I'm currently in the process of writing code for about forty or so parts
that will be done in this manner. Machining is to be started in early
January. I'll be using the same fixture for all parts and many of them will
have complex curves along one or more edges.

Smoke

> Hi Ken,
>
> This is a complex part!
>
> For the top, do the main, rectangular pocket first, and later on do the
> arc's from the side to finish.
>
> Think of the bottom work as stages, do a big pocket first, then follow
> that up with a pair of pockets.
>
> As much metal is being removed, it would be best to drill and bore while
> the block is most solid. Otherwise, it tends to get springy. Your part
> has some bored holes going across the part, If they are critical, then
> they should be done first. It is often difficult to drill and bore the
> holes from both sides, if their alignment is critical. Otherwise, it
> may not be as important when you drill them if they are just mounting
> holes.
>
> For the sequence of steps, you'll be milling in several setups. Work
> will be on top, bottom, and ALL sides! Square up a block to the
> required finish dimensions first. And select a reference corner for all
> measurements.
>
> Drill and bore the three critical cross-bores (if that's what they are)
> first.
>
> Drill and bore the front hole (does it go through to the back?) next.
>
> The top holes should next be drilled and tapped, before the top is
> milled.
>
> Hog out the top, making a simple rectangular pocket down to the point
> where there are curves in the corners (we'll do that next from the
> sides).
>
> Turn part on it's side once again, and do the final metal removal to
> give you the arc's (both sides).
>
> Flip part upside down, and mill out the big rectangle down to the point
> where the center becomes an island.
>
> Then do the two deeper pockets, which at this point are just the sides
> (the center is already gone).
>
> So as I see it, you have a "part program" basically for each if the
> sides.
>
> At least that's the way I see it. I'm there are many other ways to do
> the part.
>
> Interesting project!
>
> HTH
>
> Alan KM6VV
>