Re: Generating a Sphere

--- In CAD_CAM_EDM_DRO@yahoogroups.com, Bob Bachman <bobach@v...>
wrote:

> I need to generate a 2" diameter 1/2 sphere in a block of aluminum
> to create a mold. I have a Milltronics Partner 3 axis cnc mill. How
> do I go about programing this. I assume I need to use a ball end
> mill (3/4"?) and make a series of decreasing concentric circular
> passes until I reach of a depth of 1".

Bob, If you have Vector Cad, you will find 6 different methods to
generate tool paths to cut a hemisphere in the back of the manual
under a section heading called "More than one way to skin a cat".
These methods all use wireframe drawing techniques and do not use any
of the advanced 3D surface modeling and machining methods (there are
probably 6 more methods to "Skin the Cat" if you have the Vector 3D
surfacing option). Several of the methods utilize 3D arcs to create
the toolpaths, including the decreasing-diameter-while-increasing-
depth method. Any of the methods will let you inquire as to the size
and location of the arcs involved, and you can then manually program
the G-code from the arc data. It's even easier to create the G-code
directly from the Vector drawing with VectorCam.

Fred Smith - IMService