Technical Manual TNC 360 - heidenhain - DR. JOHANNES ...

1.2 Axis designation
The coordinate axes and their directions of travel are standardized in ISO 841.
The directions of traverse may be simply determined by using the "right-hand rule."
+Z
+X
+Y
In the direction of the spindle axis the convention is:
The movement of the tool towards the workpiece is the negative direction of traverse. When
creating an NC program one proceeds as if the tool is moving and the workpiece is always
stationary.
If the machine moves the workpiece, then the direction of movement and the direction of the axis
are opposite to one another. The positive relative directions of movement are then designated +X',
+Y' etc.
+X
+X´
The fourth axis can be used either as an axis of rotation or alternatively as an extra linear axis.
While the three principal axes have the standard designations X, Y and Z, the designations of the
fourth axis can be selected by a machine parameter.
A rotational axis is designated by the letter A, B or C. The correlation with the principle axes and
determination of the direction of rotation is standardized in ISO 841.
+Z
+C
+B
+Y
+A
+X
8/95 TNC 360 1 Machine Axes 4-11