Rockwell Automation 8520-MUM 9/Series CNC Mill Operation and Programming Manual Documentation Set - Manual (Page 611)

Using Hemisphere Milling Cycles
Chapter 24
24-5
Use the G88.5 convex milling roughing cycle to rough out a convex pocket
in a workpiece. This cycle makes multiple concentric circular cuts at a
programmed width and depth from the top center of the convex
hemisphere to the outermost diameter of the convex hemisphere.
The G88.5 block used to rough out a convex pocket has this format:
G88.5 X__Y__Z__R__Q1_P__H__D__L__E__F__;
Where : Is :
X Y The coordinates that specify the center of the convex hemisphere in the selected
plane.
Z The coordinate (along the plunging axis) that specifies the base of the convex
hemisphere.
R Radius of the convex hemisphere.
Q1 Code specifying a convex hemisphere.
P Direction of roughing cut.
H Finish allowance.
D Roughing cut thickness.
L Roughing cusp height.
E Plunge feedrate.
F Roughing feedrate.
If Q1 is programmed, the control generates a convex hemisphere. The
control makes multiple concentric circular cuts at each level of the convex
hemisphere. The depth of the pocket and the diameter of each level
increases until the outer diameter of the convex hemisphere is reached.
Important: The tool should be positioned near the center of the convex
hemisphere prior to the G88.5 block. The Z coordinate of this position
determines the initial Z level or top of the pocket. This is the pre-cycle
position of the tool.
24.1.2
Convex Hemisphere
Roughing Using G88.5