Copyright Goodheart-Willcox Co., Inc. Chapter 9 CNC Mill Programming 193 If the tool starts in the center, the code will look like this: G1 X0. Y0. F20. Feed to XY 0 at 20 ipm Z−.25 Feed down to Z-.25 G41 D1 X1.5 Cutter comp left to X1.5 still in G1 at Point 1 G03 X-1.5 R3. Counterclockwise (CCW) arc to Point 2 X1.5 R3. Still in G03, CCW arc to Point 1 G1 G40 X0. Y0. G1, cancel cutter comp, move to XY 0 It is even acceptable to ramp down while cutting the arc by add- ing Z− moves onto the G03 lines, Figure 9-15. In this case, the cutter ends up at Z−.25, so the move to Point 1 will cover half of the Z-depth Goodheart-Willcox Publisher Figure 9-14. Breaking a full circle into 180° arcs allows the use of G02 and G03 commands. First arc from Point 1 to Point 2 Second arc from Point 2 to Point 1 Goodheart-Willcox Publisher Figure 9-15. While cutting an arc, the tool can also be moved in the Z axis.