6.1.2 Axis Designation
Principal axes
X, Y, Z
Algebraic signs of
the axes
Rotary axes A, B, C
6 – 6
The coordinate axes and their directions of motion are defined in the
international standard ISO 841.
An easy way to remember this system is to use the "right-hand rule":
When the programmer writes an NC program, he always assumes that the
tool (not the workpiece) is in motion. If the machine moves its workpiece-
holding element (table) in a particular axis instead of the tool, then the direction
of actual motion is opposite to the direction of axis motion. In this case the
direction of motion is designated with the same algebraic sign as the axis
direction, but with an apostrophe: +X´, +Y´ and +Z´:
The directions of the rotary axes A, B and C follow the "right-fist rule." The
fingers of the closed right hand point in the proper rotational direction of an
axis when the thumb points in the direction of the associated linear axis:
+Z
+X
+Y
+X´
+Z
+Y
+C
+B
+X
+A
HEIDENHAIN Technical Manual TNC 426, TNC 430
+X