The definition of CNC machine axes

In order to simplify programming and ensure the generality of the program, a uniform standard has been established for the naming and orientation of numerically-controlled machine tools. It is specified that the linear feed axes are denoted by X, Y, Z, and are often called basic coordinate axes. The relationship between the X, Y, and Z axes is determined by the right-hand rule. As shown in the following figure, the thumb is pointing in the positive direction of the X axis, the index finger is pointing in the positive direction of the Y axis, and the middle finger is pointing to the Z axis. Positive direction.

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The circumferential feed axes of the X, Y, and Z axes are denoted by A, B, and C, respectively.

According to the right-handed spiral rule, as shown in the figure, with the thumb finger pointing in the +X, +Y, +Z direction, the index finger, middle finger, etc. are pointing in the +A, +B, +C direction of the circular feed motion.

The feed motion of the CNC machine tool is realized by the main shaft driving the tool movement, and some by the work table with the workpiece movement. The positive direction of the above coordinate axis is the direction in which the tool does not move and the tool performs the feed motion with respect to the workpiece. If the workpiece is moving, it is indicated by the letter “'”. According to the relationship of relative motion, the positive direction of the workpiece movement is just opposite to the positive direction of the tool movement, ie:

+X =-X', +Y =-Y', +Z =-Z',

+A =-A', +B =-B', +C =-C'

The negative direction of the two movements is also opposite to each other. The orientation of the machine axes depends on the type of machine and the layout of the components.

For lathes:

- The Z axis coincides with the axis of the spindle. Moving in the positive Z direction will increase the distance between the part and the tool;

- The X axis is perpendicular to the Z axis and corresponds to the radial movement of the turret tool holder. Moving in the positive direction of the X axis will increase the distance between the part and the tool;

The Y-axis (usually dummy) together with the X-axis and Z-axis form a coordinate system that follows the right-hand rule.