Glossary · CNC and machine tools
Work offset
Also known as: Zero offset, Fixture offset, G54 offset
German: Werkstücknullpunktverschiebung
In CNC machining, a work offset is a stored shift from the machine zero point to the workpiece zero point, selected in the program (for example with G54 to G59), that defines the workpiece coordinate system.
- CNC
In one sentence
A work offset stores the shift from machine zero to workpiece zero and defines the workpiece coordinate system used by the part program.
Example
The setter probes the vise jaw and the part top, and the control stores the zero point in G55 for the second fixture.
How it applies
- Setup: After clamping a part or fixture, the setter determines the workpiece zero, for example with an edge finder or probe, and stores it in a work offset register.
- Programming: The program selects the work offset; the selection is a Modal command on most controls. Several offsets allow several parts or fixtures on one table.
- Operation: A wrong or unselected work offset shifts the whole program and is a typical cause of collisions. Controls often display the active offset; operators should check it before starting.
- Documentation: Setup sheets must state which offset register belongs to which fixture and where the zero point sits on the part, ideally with a sketch. Keep the naming consistent with the part program comments.
Work offset vs. tool offset
The work offset locates the part; the Tool offset describes the tool. Both registers live in the control's offset tables, but they correct different things.