Wuhan Huazhong Numerical Control Co., Ltd HNC-18iT v4.0 Programming Manual page 12

1.4.2 1.4.2 Machine Machine
1.4.2 1.4.2 Machine Machine Coordinate
The coordinate system is set on a CNC machine tool. Figure 1.8 is a machine coordinate
system of turning machine, and shows the direction of axes:
In general, three basic linear coordinate axes of motion are X, Y, Z. Moreover, X, Y, Z axis
of rotation is named as A, B, C correspondently. Due to different types of turning machine,
the axis direction can be decided by following the rule – "three finger rule" of the right
hand.
- The thumb points the X axis. X axis controls the cross motion of the cutting tool.
"+X" means that the tool is away from the spindle centerline
- The index points the Y axis. Y axis is usually a virtual axis.
- The middle finger points the Z axis. Z axis controls the motion of the cutting tool.
"+Z" means that the tool is away from the spindle.
Coordinate Coordinate System System
Coordinate System System
Figure 1.8 Machine Coordinate System
+ Y
+ X ＇
+ Z
Figure 1.9 "three finger rule"
+ Y
+ B
+ Z ＇
+ X
+ C + A
+ Z
+ Y ＇
+ X
8
+X + Y + Z
+ A + B
+ C
1. General