Glossary · CNC and machine tools
Workpiece coordinate system
Also known as: Work coordinate system
German: Werkstückkoordinatensystem
In CNC machining, the workpiece coordinate system is the coordinate system whose origin is set at the workpiece zero point, so the part program can use coordinates taken from the part drawing.
- CNC
- Standards
In one sentence
The workpiece coordinate system has its origin at the workpiece zero, so part programs can use coordinates from the drawing.
Example
The programmer places the workpiece zero at the center of the bore, so all hole positions on the drawing can be programmed directly.
How it applies
- Programming: The programmer chooses a workpiece zero that matches the drawing's dimensioning, for example a corner or a bore center. The CAM system and the setup sheet must use the same zero.
- Setup: The workpiece coordinate system is established on the machine through a Work offset relative to the Machine coordinate system.
- Documentation: The setup sheet should show the workpiece zero and the axis directions on a sketch of the part and fixture. A mismatch between drawing, CAM and setup sheet is a classic source of errors that clear documentation prevents.
Workpiece vs. machine coordinate system
The machine coordinate system is fixed by the machine builder. The workpiece coordinate system is defined per setup and can change with every job. In robotics, the comparable concept is often called the user or base frame.