1. Machine origin and reference points of CNC machine tools
The machine tool origin of a CNC machine tool, also known as the mechanical origin, is the origin of the machine coordinates.
This point is a fixed point on the machine, the position of which is determined by the machine design and manufacturing unit, usually does not allow the user to change.
The machine tool origin point is the reference point for the workpiece coordinate system, the programming coordinate system, and the machine tool reference.
This point is not a hardware point, but a defining point.
The machine tool reference point is unique to CNC machines that use incremental measurement, the machine origin is reflected by the machine tool reference point.
The machine reference point is a hardware point.
2. CNC machine tool coordinate system
The origin of the workpiece coordinate system is the workpiece origin, also called the workpiece zero point.
Unlike the machine coordinate system, the workpiece coordinate system is artificially set, the general principle of choosing the origin of the workpiece coordinate system is:
1）If possible, it is selected on the base of the workpiece pattern to facilitate calculation and reduce errors for programming.
2）If possible, it is selected on the surface of the workpiece with high dimensional accuracy and low roughness value to improve the machining accuracy of the machined parts.
3) It should be easy to measure and inspect.
4）For symmetrical workpiece, it is better to choose the symmetrical center of the workpiece.
5) For general parts, it should be selected on a corner of the outer contour of the workpiece.
6) The origin of the Z-axis direction is generally located on the surface of the workpiece.