G73 G-Code Command
G73 is a G-code command used in CNC machining to perform peck drilling operations. Peck drilling is a process where the drill bit is repeatedly withdrawn from the hole being drilled to clear the chips and then re-entered to continue drilling. The G73 command specifies the depth of each peck and the total depth of the hole to be drilled. It also allows for the use of dwell time, which is a pause between pecks to allow for chip clearing and cooling. The G73 command is commonly used in the production of deep holes and can be found in many CNC machine programming languages. G73 is is commonly referred to as a high speed drilling cycle.
does the drill fully retract during a g73 canned cycle?
Unlike the G83 drilling cycle, the drill bit does not fully retract during a G73 canned cycle. In a G73 cycle, the drill bit is withdrawn only a short distance from the bottom of the hole being drilled, typically a few millimeters, to allow for chip breaking, chip evacuation and cooling. This process is repeated until the desired depth of the hole is reached. The amount of retraction is determined by the programmer and can be adjusted based on the material being drilled, the size of the hole, and other factors. The G73 cycle is designed to optimize the drilling process by reducing the risk of chip buildup and overheating, which can cause damage to the drill bit and the workpiece.
How G73 G-Code Command Is Used
Here is an example of a G73 canned cycle program with comments:
N10 G90 G54 G00 X0 Y0 Z50 ; Absolute positioning and move to the starting position
N20 S2000 M03 ; Spindle on at 2000 RPM
N30 G43 H01 Z5 ; Tool length compensation and move to the approach position
N40 G73 Z-20 Q1 R5 F20; Peck drilling cycle to drill a 20mm deep hole with 1mm peck depths and a 5mm retract height
N45 G80 ; Cancels the drilling cycle
N50 G00 Z50 ; Rapid retract to clear the hole
N60 M05 ; Spindle stop
N70 G91 G28 Z0 ; Return to home position
N80 G90 ; Absolute positioning
N90 M30 ; End of program
In this example, the program starts by positioning the tool at the starting position and turning on the spindle at 2000 RPM (N10-N20). The tool is then moved to the approach position with tool length compensation applied (N30). The G73 canned cycle is then used to peck drill a 20mm deep hole with 5mm peck depths and a 5mm retract (N40). After each peck, the tool is retracted a short distance above the current depth to clear the chips (Q5) and allow for cooling. The program then rapidly retracts the tool to clear the hole (N50), stops the spindle (N60), and returns the tool to the home position (N70). Finally, the program ends with the tool in the absolute position and the spindle off (N80-N90).
