This parameter is used to set 3 or 4 axis motion.
When 4 Axis motion is selected, one rotary axis and three linear axes are used to cut the surface. When 3 Axis motion is selected, one rotary axis and two linear axes are used dependent upon the axis of rotation. When the axis of rotation is on the X axis, no Y axis motion occurs. When the axis of rotation is along the Y axis, no X axis motion occurs. When the axis of rotation is not along any standard axis, all 4 axis motion may occur.
When 3 Axis is selected, the operation is performed with the tool tip pointing through the axis of rotation. When Swarf cutting, the Side Angle entry in the 4-5 Axis Swarf dialog box (displayed after you select a surface) has no effect on the tool angle. The tool is always pointing through the axis of rotation.
During 4 axis simultaneous motion, the tool orientation is often normal to the surface.