Axis Configuration for Horizontal Spindle CNC Machines:
The first axis to be identified is the Z axis. This is then followed by the X and Y axes respectively.
Z Axis and Motion:
Location: The Z axis motion is either along the spindle axis or parallel to the spindle axis. In the case of machine without a spindle such as shapers and planers, it is identified as the one perpendicular to the work holding surface, which may or may not be passing through the control point (e.g. the cutting tool tip in case of shaper).
Direction: The tool moving away from the work holding surface is designated as positive Z direction. This means during machining tool moves in negative Z direction.
X Axis and Motion:
Location: It is perpendicular to the Z axis and should be horizontal and parallel to the work holding surface wherever possible.
Direction: When looking from the principal spindle to the column, the positive X is to the right. For turning machines it is radial and parallel to the cross slide.
Y Axis and Motion: It is perpendicular to both X and Z axes and the direction is identified by the right hand Cartesian coordinate system.
Rotary motions: A, B and C define the primary rotary motions.
Location: These motions are located about the axis parallel to X, Y and Z respectively.
Direction: Positive A, B and C are in the directions which advance right-hand screws in the positive X, Y and Z directions respectively.