G12.1 is a CNC code and used to perform polar coordinate interpolation in CNC Lathe machines.
Polar coordinate interpolation is a function that exercises contour control in converting a command programmed in a Cartesian coordinate system to the movement of a linear axis (movement of a tool) and the movement of a rotary axis (rotation of a workpiece). This function is useful in cutting a front surface and grinding a cam shaft for turning.
G12.1 Code Examples for CNC Lathe
Example – 1
G00 X120.0 C0 ; Positioning at the cutting start point
G12.1 ; Polar coordinate interpolation mode ON
G01 G42 X40.0 F100.0 ;
G03 X0 C40.0 I–20.0 ;
G01 X–25.0 ;
G03 X–40.0 C25.0 K–15.0 ;
G01 C0 ;
G03 X20.0 I20.0 ;
G01 G40 X120.0 ;
G13.1 ; Polar coordinate interpolation mode OFF