8 Basic CNC Programming
8.4 NC Codes
117
Absolute
G90
The X coordinate of the arc/circle center, measured from the origin.
Note: In Fanuc mode, all arc centers are specified in incremental mode.
Incremental
G91
The distance along the X direction from the starting point of motion to the
arc/circle center.
The I code is also used with the G51 code to specify the scale factor for the X axis when performing
scaling functions, including scaling each axis and mirror scaling. See
8.4.6.10 Scaling Group, pg. 114.
8.4.9.
J Code: Y Axis Coordinate of Center Point
The J code specifies the Y coordinate of the center of an arc or circle. If no J code is specified when
specifying an arc or circle, the system uses the current Y axis location as the Y axis center of the arc.
The J code is used in both absolute and incremental programming modes. In Fanuc mode, all arc centers
are specified in incremental mode.
The value following the J code is interpreted differently in absolute and incremental programming
modes, as follows:
Info Table: J Code in Absolute and Incremental Modes
Mode
Activated by
J value specifies:
Absolute
G90
The Y coordinate of the arc/circle center, measured from the origin.
Note: In Fanuc mode, all arc centers are specified in incremental mode.
Incremental
G91
The distance along the Y direction from the starting point of motion to the
arc/circle center.
The J code is also used with the G51 code to specify the scale factor for the Y axis when performing
scaling functions, including scaling each axis and mirror scaling. See
8.4.6.10 Scaling Group, pg. 114.
8.4.10.
K Code: Z Axis Coordinate of Center Point
The K code specifies the Z coordinate of the center of an arc or circle. If no K code is specified when
specifying an arc or circle, the system uses the current Z axis location as the Z axis center of the arc.
The K code is used in both absolute and incremental programming modes. In Fanuc mode, all arc centers
are specified in incremental mode.
The value following the K code is interpreted differently in absolute and incremental programming
modes, as follows:
Info Table: K Code in Absolute and Incremental Modes
Mode
Activated by
K value specifies:
Absolute
G90
The Z coordinate of the arc/circle center, measured from the origin.
Note: In Fanuc mode, all arc centers are specified in incremental mode.
Incremental
G91
The distance along the Z direction from the starting point of motion to the
arc/circle center.
The K code is also used with the G51 code to specify the scale factor for the Z axis when performing
scaling functions, including scaling each axis and mirror scaling. See
