G69 is a Gcode command that cancels the coordinate system rotation that was previously set by G68. Coordinate system rotation is a feature that allows the programmer to rotate the coordinate system by a specified angle around a specified point. This can be useful for machining parts that are not aligned with the machine axes, or for creating complex patterns or shapes.
Usage format
The usage format of G69 is:
G69
There are no parameters required for G69. It simply cancels the coordinate system rotation that was active.
Explanation
When G69 is executed, the coordinate system returns to its original orientation, as defined by the current work offset (G54 to G59). Any subsequent commands will use the unrotated coordinate system, unless another G68 command is issued.
G69 does not affect the current position of the tool or the workpiece. It only changes the way the coordinates are interpreted by the machine. Therefore, it is important to use G69 carefully and avoid any unwanted movements or collisions.
Example
Here is an example of using G69 to cancel a coordinate system rotation. Assume that the work offset is G54 and the coordinate system is rotated by 30 degrees counterclockwise around the point (10, 10) using G68.
G54 ; select work offset
G68 X10 Y10 R30 ; rotate coordinate system by 30 degrees CCW around (10, 10)
G01 X20 Y20 F100 ; move to (20, 20) in the rotated coordinate system
G69 ; cancel coordinate system rotation
G01 X30 Y30 F100 ; move to (30, 30) in the original coordinate system
The text diagram below shows the effect of G69 on the coordinate system and the tool path. The dashed lines represent the rotated coordinate system, and the solid lines represent the original coordinate system.
Y
^

 / (30, 30)
 /
 /
 /
 /
 /
 /
/ (20, 20)
+> X
/
/ 
/ 
/ 
(10, 10)