Re: [CAD_CAM_EDM_DRO] Generating a Sphere

Hi Bob:
The approach you suggest will not give you a very nice cavity unless you
decrease the depth of cut radically as you approach the bottom.
I would program this as a radial type toolpath where the cutter walks from
the center outward to the periphery, makes a 1 degree move around the outer
circumference, and then walks back into the center (repeated ad nauseum to
get the hemisphere).
Of course, the cavity will need to be roughed out first.
Your concentric circle milling strategy is great for that, but don't bother
to use a ballcutter.
I usually just helical down to each Z level with a 5/8 or so carbide mill,
and then pocket out each level, until I'm down.
Then I take the biggest ballcutter I've got for the semifinish and finish
passes.
Leave about 0.005" for the finish pass and flood cool if you can.
Cheers

Marcus

----- Original Message -----
From: "Bob Bachman" <bobach@...>
To: <CAD_CAM_EDM_DRO@yahoogroups.com>
Sent: Thursday, October 09, 2003 8:25 PM
Subject: [CAD_CAM_EDM_DRO] Generating a Sphere


> 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
>
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