G73 is a G-code command that is used to perform a high speed peck drilling cycle on a CNC machine. Peck drilling is a technique that involves retracting the drill bit slightly after each cut, to break the chips and prevent them from clogging the hole. This can improve the drilling efficiency and quality, especially for deep holes or difficult materials.

Usage format

The general format of the G73 command is:

G73 X Y Z R Q F

where:

• X and Y are the coordinates of the hole center
• Z is the depth of the hole (negative value)
• R is the position of the rapid plane (positive value)
• Q is the peck depth (positive value)
• F is the feed rate

Explanation

The G73 command performs the following sequence of operations:

• Rapid move to the XY position of the hole
• Rapid move to the R plane
• Feed move to the first peck depth (Q)
• Rapid retract to the R plane
• Feed move to the second peck depth (2Q)
• Rapid retract to the R plane
• Repeat until the final depth (Z) is reached
• Rapid retract to the initial plane

The G73 command is similar to the G83 command, which is another peck drilling cycle, but with some differences. The main difference is that the G73 command retracts only to the R plane, while the G83 command retracts to the initial plane. This makes the G73 command faster, but less suitable for chip removal. Another difference is that the G73 command uses a fixed peck depth (Q), while the G83 command uses an incremental peck depth (Q).

Example

Here is an example of using the G73 command to drill four holes in a rectangular pattern:

G90 G54 G00 X10 Y10 S1200 M03 ; Set absolute mode, select coordinate system, move to first hole, set spindle speed and direction
G43 H01 Z2.0 M08 ; Activate tool length compensation, move to clearance plane, turn on coolant
G73 X10 Y10 Z-20 R2.0 Q4.0 F100 ; Peck drill first hole
X40 ; Peck drill second hole
Y40 ; Peck drill third hole
X10 ; Peck drill fourth hole
G80 ; Cancel canned cycle
G00 Z2.0 M09 ; Move to clearance plane, turn off coolant
G91 G28 Z0 M05 ; Return to reference position, stop spindle
M30 ; End of program