What I'm trying to do is machine a convex segment of a hemisphere.
Yes, I know it would be a slam dunk with a lathe, but I'd like to do it on the mill (no manually cranking handles, thank you).
The dimensions of the hemisphere: R1- base radius - .3935"
R2- top radius - .1625" If you look closely at the setup pics you can see there is a .325" hole in the center of the stock.
Tool: 3/8" ball end mill (tip radius .1875")
If my math is correct the finished height (H) of the segment will be .231" ( R1 - R2 = H )
The formula seems too simple, am I missing something??
I figure that the program will be a series of circular cuts beginning at the edge of the center hole with each successive cut being .001" larger in diameter as the tool
progresses downward .001" from Z-0.
What I'm having trouble wrapping my head around is the relationship between the radius of the segment and the radius of the tool.
At Z-0.001 the tip of the tool will be engaged on the top of the stock. As the cut progresses the the engagement point will steadily move away from the tool center (zero radius) towards the side of the tool and full radius at a cut depth of .1875".
Can Mach do this, or do I have to program the X-Y circular moves to compensate for the increasing cutter radius?
Here's a couple of pics of the setup, any constructive comments will be greatly appreciated.
Thanx,
Rex