Optimizing CNC Drilling: G81 Cycle on Grid Plate – Practical Sample Program

CNC machine workshops deal with variety of components, of course cnc machinists program and machine them.
But a cnc machinists also should understand and practice new and economical ways to machine a component.

The following cnc programming example can be programmed in variety of ways, the method of cnc programming used in this cnc program sample uses G81 drilling cycle with G91 Incremental Programming mode, which makes programming easy.

Fanuc cnc control uses K with G81 drilling cycle to repeat drilling cycle.
Haas cnc controls use L to repeat G81 drilling cycle.

Following cnc program is written for haas cnc machine but can easily be converted for Fanuc cnc controls.

You might read other cnc programming example which shows the same technique for Fanuc cnc controls

• G81 Drilling Cycle – Repeat Drilling in G91 Incremental Mode Example Code
• Repeat Drilling with G81 Drilling Cycle and G91 Example Program

CNC Program of Drilling Grid Plate

Drilling Grid Plate with G81 Drilling Cycle

03400      (Drilling grid plate)
T1 M06
G00 G90 G54 X1.0 Y-1.0 S2500 M03
G43 H01 Z.1 M08
G81 Z-1.5 F15. R.1
G91 X1.0 L9
G90 Y-2.0   (Or stay in G91 and repeat Y-1.0)
G91 X-1.0 L9
G90 Y-3.0
G91 X1.0 L9
G90 Y-4.0
G91 X-1.0 L9
G90 Y-5.0
G91 X1.0 L9
G90 Y-6.0
G91 X-1.0 L9
G90 Y-7.0
G91 X1.0 L9
G90 Y-8.0
G91 X-1.0 L9
G90 Y-9.0
G91 X1.0 L9
G90 Y-10.0
G91 X-1.0 L9
G00 G90 G80 Z1.0 M09
G28 G91 Y0 Z0
M30

In above cnc program G90 Absolute programming mode is used while starting a new row for drilling. Although G91 Incremen0tal programming can be used but using G90 there makes this program easy to read understand and debug (if anything goes wrong).