How do you mill a sphere?

[rapidtraverse]

Hi All,

I have been tasked to mill a concave spherical shape in a piece of mild steel.

I was wondering if anyone has a parametric program and is willing to share the code.

I don't have a CAM softwear to refer to.

Thanks

[Ginger_Ninja54]

what language are you using?
you can do a sphere with heidenhain with about 6 lines!
i may be able to write it in fanuc (haas) but it might take me a minute or so!!!

[Kiwi]

Here is a program which may help.

[High Seas]

Kiwi - That is AWESOME, Mate!
So, now I can make a basketball in 2 halves.
Do you have a routine to share for an ellipsoid - for rugby?
Actually, I'd kinda like it if the axes (major and minor) could be adjusted independently. Anything there on that hard drive of yours?

Anyway - thanks for sharing that.
Jim

[Kiwi]

High Seas
The program is for a concave (female) sphere, not convex (male)
The program will need modifying to cut convex.
Here is a program to produce a ellipse. I'll look at what can be done.

[High Seas]

Sweeeet AS Mate!
Cheers
Jim

[rapidtraverse]

Thank you!

Code is for Fanuc.

Everything posted is super!

Kiwi, is your program called a parametric program with "if" and "then" statements?


Does anyone have code for a parametric program like this? I'd like to use it as a Macro.

Thanks again

[Kiwi]

rapidtraverse
My program is written in Visual Basic.
This is part of the program trimmed which generates the X Y Z curve
The 'For' part will need to be replaced with 'While Angle NE 0' or something similar.

For Angle = 0 To 90
#101 = (SphereRadius - CutterRadius) * Cos(Angle)
#103 = (SphereRadius - CutterRadius) * Sin(Angle)
#103 = #103 + CutterRadius
#104 = 0-#103

G01 X#101 Y0 Z#103 F?
G03 X#101 Y0 I#104 J0 F??
Next Angle

[Kiwi]

HighSeas
New version of program which will generate code for a convex half-sphere.
Not sure I can write a program to generate code for a ellipsoid (rugby ball).
Because the steepness of the side changes this is difficult to calculate when using a ballnose cutter.
Could do it for a flat endmill but would be very rough finish.
Not sure what it would look like if use this path with a ballnose cutter.

[300sniper]

thanks kiwi!

i am new to cnc and a friend just asked if i could make him a mold for making lead down-rigger weights. i had been trying to figure how to machine a concave sphere for this. i was thinking using the 4th axis was going to be the only way i could do it with out 3d cad/cam which i don't have.

[Kiwi]

Originally Posted by High Seas Do you have a routine to share for an ellipsoid - for rugby? Actually, I'd kinda like it if the axes (major and minor) could be adjusted independently. Anything there on that hard drive of yours? Jim

Jim
I've finally got this program done.
It's not quite perfect, it cuts a little oversize on the curved face. (like a slightly over inflated rugby ball.)

[High Seas]

Kiwi - found the link --
Thats great Mate! Thanks, and
Jim