Machine coordinate system, machine zero and machine reference point

The machine coordinate system is the machine's unique coordinate system. The origin of the machine coordinate system is called the machine origin or machine zero. After the machine tool is designed, manufactured and adjusted, this origin is determined and it is a fixed point.

When the CNC device is powered on, it does not know the machine zero point. In order to correctly establish the machine coordinate system when the machine tool is working, a machine tool reference point (measurement starting point) is usually set within the moving range of each coordinate axis. When the machine starts, it is usually performed. Maneuver or manually refer back to the machine coordinate system.

The machine tool reference point can coincide with the machine zero point, or it can not coincide, and the distance between the machine reference point and the machine zero point can be specified by the parameter.

When the machine tool returns to the reference position, it knows the zero position of the coordinate axis, finds the reference points of all coordinate axes, and the CNC establishes the machine coordinate system.

The mechanical travel of the machine axes is limited by the maximum and minimum limit switches. The effective travel range of the machine axis is defined by the software limit and its value is defined by the manufacturer. The relationship between machine zero (OM), machine tool reference point (Om), and the mechanical stroke and effective stroke of the machine coordinate axis is shown in the figure below.

Fig. Machine zero point OM and machine tool reference point Om