G73: Chip Drilling Cycle

G73 X- Y- Z- R- Q- <L->

• R – retract position along the Z axis;
• Q – delta increment along the Z axis;
• L – repeat count.

The G73 cycle is drilling or milling with chip breaking. This cycle takes a Q number which represents a delta increment along the Z axis.

1. Preliminary motion:
   If the current Z position is below the R position, The Z axis does a rapid move to the R position.
   Move to the X Y coordinates.
2. Move the Z-axis only at the current feed rate downward by delta or to the Z position, whichever is less deep.
3. Rapid up a bit.
4. Repeat steps 2 and 3 until the Z position is reached at step 2.
5. The Z axis does a rapid move to the R position.