This is an explanation of our 4 axis milling center with a rotary table.
The C-axis control the rotation of the table. The direction of motion is defined by the sign of the C value. Since the table rotates the workpiece, the table must rotate clockwise to achieve a counterclockwise tool motion and vice versa.
C+ = Counterclockwise workpiece rotation (viewing in the Z+ direction). C- = Clockwise workpiece rotation.
G90 Absolute Mode
In the absolute mode (G90), the C-word value defines the final position between 0 and 360. The + or - signs define the direction of rotation. The + sign causes counterclockwise workpiece rotation, the - sign causes the clockwise rotation to the indicated degree. There are two possible ways to get to a position on the rotary table in absolute: by rotating either from the positive or negative direction.
G91 Incremental Mode
In the incremental mode (G91), the C axis value defines the direction and number of degrees to rotate. A C+90, causes the workpiece to rotate counterclockwise 90 degrees. If the next move were a C-90, the workpiece would rotate clockwise to the original position.
For G00 and G01 only
The C-axis in this machine will work in conjunction with linear moves (G00 and G01) only. Arcs (G02 and G03) will not work with the C-axis.