Glossary · CNC and machine tools
Machine coordinate system
Also known as: Machine coordinates, MCS
German: Maschinenkoordinatensystem
In CNC machine tools, the machine coordinate system is the coordinate system fixed to the machine, with its origin at the machine zero point defined by the machine builder, to which all other coordinate systems are referenced.
- CNC
- Standards
In one sentence
The machine coordinate system is fixed to the machine tool with its origin at the machine zero; all other coordinate systems refer to it.
Example
After power-on the axes are referenced, so the control knows the tool position in machine coordinates before the work offset G54 is applied.
How it applies
- Engineering: ISO 841 defines the axis naming and directions (right-hand rule, Z along the spindle). The machine builder sets the machine zero point and the software limit switches in machine coordinates.
- Commissioning: Axes with incremental encoders must be referenced after power-on before the control can use machine coordinates; axes with absolute encoders keep their position.
- Operation: Operators rarely program in machine coordinates; they use a Workpiece coordinate system set through a Work offset.
- Documentation: The operating manual should show the machine zero, reference point and axis directions in a drawing, and explain the referencing procedure. Software travel limits relate to Machine limits and must match the risk assessment.
Machine vs. workpiece coordinate system
The machine coordinate system never moves. The workpiece coordinate system is shifted to a convenient point on the part so the programmer can use drawing dimensions.