Circular interpolation is a critical function in CNC machining, allowing the tool to move along a circular path. The G02 G code is used in Fanuc controls to perform clockwise circular interpolation.
Usage Format
The basic format for G02 in Fanuc systems is:
G02 X_ Y_ I_ J_ F_
 X and Y are the end point coordinates of the arc.
 I and J are the distance from the starting point to the center of the arc along the X and Y axes, respectively.
 F is the feed rate.
Explanation
When programming a G02 move, you must specify the end point of the arc and the center point relative to the start. The control uses these points to calculate the radius and determine the arc’s path.
Example
Let’s consider an example where we want to move the tool in a quartercircle arc from the current position to a point 10 units right and 10 units up, with a radius of 10 units.
Text Diagram:
Current Position (Start)

 (End)
 /
 /
 / R=10
 /
/
G Code:
G02 X10 Y10 I0 J10 F5
This code tells the machine to move in a clockwise arc from the current position to a point 10 units in the positive X direction and 10 units in the positive Y direction, with the center of the arc 10 units directly above the starting point on the Yaxis, at a feed rate of 5.